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  • Analytical Chemistry and Spectroscopy  (566)
  • pharmacokinetics
  • Wiley-Blackwell  (566)
  • Springer  (23)
  • 1980-1984
  • 1975-1979  (589)
  • 1976  (589)
Collection
Publisher
  • Wiley-Blackwell  (566)
  • Springer  (23)
Years
  • 1980-1984
  • 1975-1979  (589)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 10 (1976), S. 55-58 
    ISSN: 1432-1041
    Keywords: Penicillin V ; bioavailability ; pharmacokinetics ; dose ranging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary An absorption study was performed in ten healthy volunteers to test the bioavailability of various doses of two penicillin V-K preparations: Isocillin® (Hoechst AG, Federal Republic of Germany), — tablets of 600 000 and 1.2 Mega U; V-Cillin® (Eli Lilly, USA), — tablets of 200 000, 400 000 and 800 000 U. The serum concentrations and elimination of the active substance in urine were measured for six hours after administration. Independently of the source of the preparation, a strict linear relation between the dose and the area under the serum curve (AUC), or between the dose and the urinary elimination, was demonstrated by regression analysis. The dose-dependent increase in the AUC was highly significant (p〈0.01) in the range tested, i.e. between 200 000 and 1.2 Mega U. The relative elimination of active substance in urine lay within narrow limits for all doses (35.7–41.3%). Thus, both compounds proved to have the same bioavailability.
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  • 2
    ISSN: 1432-1041
    Keywords: Ampicillin ; bioavailability ; pharmacokinetics ; branded products ; proprietary preparations ; capsule formulation ; tablet formulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics and bioavailability of three different brands of ampicillin were studied in 10 volunteers. After intravenous administration ampicillin can be described adequately by a two-compartment open pharmacokinetic model. The half-life during the α-phase was 9 min and the β-half-life was in the range 50–60 min, independent of the mode of administration. Absolute bioavailability was determined from the ratio of the areas under the serum concentration curves obtained after oral and intravenous administration of equal doses. Bioavailability was also estimated by analysis of variance. The results indicated absolute availability of the three products of 39–54%. One of the products, a capsule formulation, showed a significantly lower bioavailability than the others, which were tablet formulations.
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  • 3
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    European journal of clinical pharmacology 10 (1976), S. 257-262 
    ISSN: 1432-1041
    Keywords: Anti-inflammatory and analgesic drug ; indoprofen ; pharmacokinetics ; bioavailability ; man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In a pharmacokinetic study of the new analgesic and anti-inflammatory drug indoprofen, plasma levels and urinary excretion were determined in four healthy volunteers after 100 mg and 200 mg iv, and after 100 mg (capsules) and 200 mg (tablets) oral doses. After iv administration, the mean biological half-life (t1/2 β) was about 2 h (range 1.4 to 3.2 h). The apparent volume of distribution Vdβ ranged between 11 to 17 % of body weight, indicating its limited extravascular distribution. Most of the drug was excreted in urine as glucuronide and a smaller proportion as unchanged indoprofen: the 24 h urinary excretion of these compounds accounted for 67 to 95 % of an iv dose. Peak plasma levels occurred between 30 and 120 minutes after oral administration of 100 mg as capsules or 200 mg as tablets. The mean biological half-life was about 2 h, as after iv administration. The bioavailability of oral doses was assessed using both plasma levels and urinary excretion data. The absorption of capsules and tablets was practically complete, that of the former being faster.
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  • 4
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    European journal of clinical pharmacology 10 (1976), S. 263-271 
    ISSN: 1432-1041
    Keywords: Butobarbital ; pharmacokinetics ; plasma concentration ; oral administration ; accumulation ; enzyme induction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A method is described for the assay of therapeutic levels of butobarbital (5-ethyl-5-n-butylbarbituric acid) in human plasma, which involves a single extraction step followed by gas chromatography with alkali flame ionization detection. The pharmacokinetics of butobarbital were studied in five healthy volunteers after oral administration of 200 mg. Plasma concentrations were determined at regular intervals up to 96 h and the data were fitted by non-linear, least squares regression analysis according to one-compartment kinetics. The average lag time was 0.11 h and the absorption half-life 0.21 h. The elimination half-life varied from 33.6 to 41.5 h with an average of 37.5 h. Four of the volunteers participated in a study of multiple dosing (every 24 h) during which substantial accumulation of butobarbital was observed. The elimination half-life after termination of drug administration had decreased to about 20–25% of its initial value, probably because of enzyme induction. It was concluded that butobarbital could not be regarded as a suitable drug for treatment of insomnia, since CNS depressant effects were likely to persist into the following day. Repeated administration of butobarbital should be avoided and its incidental use restricted to patients who require day-time sedation.
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  • 5
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    European journal of clinical pharmacology 10 (1976), S. 293-295 
    ISSN: 1432-1041
    Keywords: Bendroflumethiazide ; diuretics ; GLC ; thiazides ; plasma level ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A GLC method for determination of bendroflumethiazide has been developed, using extractive methylation. Cyclopenthiazide was used as internal standard. The maximal plasma concentration (56–107 ng/ml) after bendroflumethiazide 10 mg given orally to four healthy volunteers was seen at 2–2.5 h. On the slope between 4 and 10 h T1/2 averaged 2.7 h.
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  • 6
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    European journal of clinical pharmacology 10 (1976), S. 337-341 
    ISSN: 1432-1041
    Keywords: Amitriptyline ; pharmacokinetics ; intravenous infusion ; two compartment model ; biological half-life
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Amitriptyline was given to four male volunteers by constant rate intravenous infusion. Blood samples were collected before, during and at various times after the infusion for estimation of the serum concentrations of amitriptyline. The level of nortriptyline never reached a detectable level. A two compartment open model was shown to be applicable to the data obtained. The meaning of the parameters obtained by a non-linear, least squares curve fitting procedure is discussed and the values are compared to those recently published for nortriptyline. The calculated biological half-life of amitriptyline was about 17 hours, a figure which differs considerably from previously calculated values for volunteers, but is in accordance with some newer results from patients.
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  • 7
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    European journal of clinical pharmacology 10 (1976), S. 63-68 
    ISSN: 1432-1041
    Keywords: Phenazone ; pharmacokinetics ; injuries ; surgery ; operation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The elimination rate of phenazone after a single oral dose has been studied before and after elective operations. In a group of patients with different illnesses the elimination rate was increased on the fourth to seventh days after operation but was unchanged on the second and third days. The change in elimination rate was highly significant in a standardized group of nine patients with a ligament injury in one knee studied on the fourth or fifth postoperative day. Possible reasons for the changes are discussed.
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  • 8
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    European journal of clinical pharmacology 10 (1976), S. 251-256 
    ISSN: 1432-1041
    Keywords: Sisomicin ; pharmacokinetics ; bioavailability ; two-compartment analysis ; man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of sisomicin, a new single component aminoglycoside antibiotic related to gentamicin c1a, were determined in four healthy volunteers after intravenous and intramuscular administration of a 1 mg/kg dose. The elimination profile of this antibiotic follows two-compartment model kinetics after I.V. administration. The fast (α) and slow (β) disposition rate constants averaged 0.072 and 0.004 min−1, respectively. The volume of distribution at the steady-state averaged 0.185 liters/kg which approximately corresponds to the volume of extracellular space. The physiological availability of an intramuscular dose appeared to be complete. A method of administration adapted to the kinetic properties of the drug is proposed.
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  • 9
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    European journal of clinical pharmacology 10 (1976), S. 183-187 
    ISSN: 1432-1041
    Keywords: Hydralazine ; bioavailability ; pharmacogenetics ; first pass effect ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary After oral administration of a single 50 mg dose of hydralazine (Apresoline®), the serum half-life (T1/2) and bioavailability (AUC0−∞) were assessed in 16 healthy volunteers. The half-life was 2.57±0.14 h (S.E.) in 10 slow acetylators of sulphadimidine, and 2.18±0.15 h in 6 fast acetylators (difference not statistically significant). AUC0−∞ was significantly higher in slow acetylators, at 1.04±0.10 µg·hour·ml−1, compared to 0.66±0.12 µg·hour·ml−1 in the fast acetylators (p〈0.025). Treatment with Apresoline® 25 mg tid produced minimum serum concentrations at steady-state of 57.3±7.3 ng·ml−1 and 33.4±4.2 ng·ml−1 in 8 slow and 5 fast acetylators, respectively (p〈0.05). The corresponding maximum concentrations were 228.8±20.3 ng·ml−1 and 147.6±15.0 ng·ml−1 in slow and fast acetylators, respectively (p〈0.025). First-pass metabolism of hydralazine could explain the difference in bioavailability of the drug between fast and slow acetylators, without any corresponding difference in the elimination rate of the drug in the post-distributive phase.
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  • 10
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    European journal of clinical pharmacology 10 (1976), S. 121-126 
    ISSN: 1432-1041
    Keywords: Diazepam ; pharmacokinetics ; subchronic dosage in man ; desmethyldiazepam
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In seven healthy male volunteers the effects of the pattern of dosing on the pharmacokinetics of diazepam have been studied. A cross-over design was employed that consisted of three parts: a single intravenous dose (0.1 mg/kg), and oral dosing (10 mg/day) for six days followed by an intravenous bolus (0.1 mg/kg) on the seventh day, followed by re-examination of a single intravenous dose after diazepam (D) and its major metabolite desmethyldiazepam (DD) had been completely eliminated. Plasma levels of D and DD were monitored by a specific, sensitive GLC-method. In younger patients (n=5, age 29 – 35 years) the elimination half-life, T1/2 (β), of D was 33.9±10.6 h (mean±S.D.) after the single dose. The control study gave an almost identical result (35.7±12.1). After subchronic dosage in all patients T1/2 (β) showed a modest but significant prolongation (paired t-test p〈0.01) to 52.9±17.4 h. It was caused by a significant decrease (p=0.016) in total plasma clearance ( $$\overline {\user1{Cl}} $$ ), from 26.0±10.8 ml/min to 18.2±7.0 ml/min. Older patients (age 43–60 years) showed the same phenomenon. Blood/plasma ratios remained constant indicating no change in protein binding. Biliary excretion of D was measured in five patients with a T-tube. Only negligible amounts (0.3–0.4%) of administered D were excreted within 3 days after subchronic dosage, which demonstrates a lack of enterohepatic cycling of D. After multiple administration of D, there was accumulation of DD to levels approximately five times higher than after a single dose. The possibility that the slower elimination of D after subchronic treatment might be caused by DD was also supported by experiments in dogs and rabbits. After pretreating rabbits with DD and maintaining a high DD plasma level, there was prolongation of T1/2 (β) from 2.7 h to 5.2 h, with a corresponding decrease of $$\overline {\user1{Cl}} $$ from 101.6 ml/min to 23.4 ml/min. Similar results were obtained in dogs. It is concluded that the disposition of D is altered by subchronic use and may be regulated by the plasma DD concentration.
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  • 11
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    European journal of clinical pharmacology 10 (1976), S. 311-317 
    ISSN: 1432-1041
    Keywords: Hydralazine ; instability of impaired renal function ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Following a single 50 mg dose of hydralazine (Apresoline®) in 13 patients with impaired renal function, a decrease in glomerular filtration rate (GFR) was correlated with an increase in serum half-life (T1/2) of the drug (r=−0.69; p〈0.01). The T1/2 was 15.8 h in one patient with a GFR of 16 ml·min−1, as compared to a T1/2 of 1.7–3.0 h found previously in 16 healthy volunteers. In 49 patients on long-term antihypertensive treatment with hydralazine, the ratio between the minimum steady-state drug concentration and the daily dose of hydralazine (C SS min : Dose) increased as the GFR decreased. This accumulation of the drug was particularly evident in patients with a GFR less than 30 ml·min−1 (r=−0.63; p〈0.01; n=19). As renal excretion of unchanged hydralazine is generally regarded as unimportant, the slower elimination rate in chronic renal failure was probably caused by a slower rate of metabolic conversion. It was found, however, that the renal excretion of hydralazine could easily have been underestimated, as only 12.7% of an initial hydralazine concentration of 200 ng·ml−1 in urine could be recovered after storage of the samples at room temperature for 24 h.
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  • 12
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    European journal of clinical pharmacology 10 (1976), S. 325-330 
    ISSN: 1432-1041
    Keywords: Flutiorex ; pharmacokinetics ; sex ; anorectic agent ; sympathetic stimulation ; CNS stimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effects of flutiorex, a new anorectic agent, and of a placebo on food intake and the activity of the sympathetic and central nervous systems have been compared in a double blind trial in two groups of healthy volunteers, one of five males and the other of five females. Flutiorex 20 mg orally had a significant anorectic effect both in males and females, the observed reduction in food intake being 34.0 and 27.5%, respectively. It caused α-adrenergic stimulation (blood pressure and pupil diameter) and central nervous system excitation (critical flicker frequency), both of which were more marked in males than in females. Flutiorex was better tolerated by women than by men. Measurement of the blood level of flutiorex and its de-ethylated metabolite, norflutiorex, showed that both compounds were detectable in four of the five male subjects, but in only one of the five females. Sex-linked differences in the pharmacokinetics of flutiorex may explain the greater intensity of its effects in males.
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  • 13
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    European journal of clinical pharmacology 10 (1976), S. 343-347 
    ISSN: 1432-1041
    Keywords: Methaqualone ; hypnotic ; pharmacokinetics ; combination formulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Concentrations of methaqualone have been measured in the serum of five male human subjects receiving five consecutive evening doses of a combination formulation containing methaqualone (250 mg), carbromal (300 mg) and benactyzine (0.33 mg) in each tablet. After administration of the first dose, mean peak serum concentrations of methaqualone (1.2 µg/ml) occurred at 3 h. After obtaining peak levels, mean concentrations of methaqualone declined rapidly during the next 6 h and there-after more slowly during the next 18 h. After administration of the last (fifth) dose, mean peak serum concentrations of methaqualone (1.9 µg/ml; 1.5 µg/ml above the predose level) occurred at 2 h. After attaining peak levels, mean concentrations of methaqualone declined rapidly during the next 6 h, and thereafter more slowly, with a half-life of approximately 10 h. Mean concentrations of methaqualone in serum samples 24 h after the second, third, fourth or fifth doses were not significantly different (0.3 µg/ml – 0.6 µg/ml) during this period of dosing. This suggests that significant accumulation of methaqualone in the serum did not occur during a period of five consecutive evening doses of the combination formulation.
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  • 14
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    European journal of clinical pharmacology 10 (1976), S. 25-29 
    ISSN: 1432-1041
    Keywords: Digoxin ; exchange transfusion ; pharmacokinetics ; neonates ; 86Rb assay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary By means of an86Rb-uptake inhibition assay, changes in the plasma concentration of digoxin and the amount of the glycoside removed during exchange transfusion have been studied in two newborns. For comparison, the exchange procedure was simulated by a computer on the basis of a two-compartment open model and available pharmacokinetic constants. A rapid decrease in plasma digoxin concentration during exchange transfusion was found when the glycoside was administered intravenously or intramuscularly within 60 min before the procedure. The amount of digoxin removed by the exchange was less than 6 per cent of the given dose. Computer simulation of the procedure also showed removal of only a minor amount of digoxin. It is concluded that the decrease in plasma concentration and the removal of only a small amount of glycoside by the exchange transfusion can be attributed mainly to extensive tissue distribution of digoxin. The results imply that replacement of digoxin after an exchange transfusion seems unnecessary.
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  • 15
    ISSN: 1432-1041
    Keywords: Diabetes mellitus ; drug interaction ; phenprocoumon ; pharmacokinetics ; pharmacodynamics ; sulphonylureas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The influence of various antidiabetic treatments on the kinetics and efficacy of a single oral dose of 12 mg phenprocoumon were studied in 71 hospitalized patients, 58 with adult-onset diabetes mellitus and 13 non-diabetic aged patients, and 13 healthy young volunteers. Treatment for one week or longer with insulin or the antidiabetic sulphonylureas tolbutamide, glibenclamide or glibornuride, altered neither the plasma level (1.29 – 1.40 µg/ml at zero time) nor the half-life of phenprocoumon (5.2 – 6.8 d) compared to treatment by diet alone. The mean half-life of phenprocoumon was significantly shorter in non-diabetic aged patients (4.2 d) than in diabetic patients of the same age (5.1 – 6.8 d), or in young healthy volunteers (5.7 d). The efficacy of a single dose of phenprocoumon (maximal reduction of Quick-values by 34 – 47% after 48 to 72 hrs) in diabetic patients treated with diet, or diet and antidiabetic drugs, was the same as in non-diabetic aged patients. In healthy young volunteers phenprocoumon was half as effective as in aged patients.
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  • 16
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    European journal of clinical pharmacology 9 (1976), S. 327-332 
    ISSN: 1432-1041
    Keywords: Antipyrine ; pharmacokinetics ; half-life ; blood ; plasma ; saliva ; individual variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A previously described GLC method has been modified and applied to measurement of antipyrine levels in plasma, blood and saliva of man following administration of a single oral dose (10 mg/kg). The levels in blood and saliva were comparable to those in plasma at every time studied. The half life of antipyrine determined in blood, plasma or saliva in any given individual was similar. The intersubject variation in half-life was about two-fold (n=5). Antipyrine levels in saliva were not affected by the rate of saliva flow when collections were made continuously for 20 minutes. This study has demonstrated that kinetic data about antipyrine comparable to that from plasma may also be obtained from readily accessible tissue fluids, such as saliva and capillary blood.
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  • 17
    ISSN: 1432-1041
    Keywords: Chlorthalidone ; diuretics ; drug plasma concentration ; protein binding ; red blood-cell concentration ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A gas chromatographic method has been employed to determine chlorthalidone in plasma and whole blood after therapeutic doses. Radioactively labelled chlorthalidone was used for in vitro studies of the uptake of chlorthalidone from plasma by red blood cells. Chlorthalidone was markedly concentrated in red cells and as a compartment they would account for at least 30% of total drug in the body after multiple doses. The ratio between the plasma and red cell concentration of chlorthalidone varied between individuals. After a single oral dose of 50 mg in 6 healthy volunteers chlorthalidone was eliminated with a half-life of 51 to 89 hours. The apparent volume of distribution varied between 3 and 13 1/kg and the clearance between 53 and 145 ml/min. The mean steady-state plasma concentrations during treatment with a standard dose of 50 mg daily (n=10) varied 5-fold between individuals. During the steady state approximately 50% of the daily dose was excreted unchanged in the urine during 24 hrs. The plasma levels observed in patients were higher than those predicted from the single oral dose studies in healthy volunteers.
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  • 18
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    European journal of clinical pharmacology 9 (1976), S. 367-372 
    ISSN: 1432-1041
    Keywords: Sotalol ; β-adrenoceptor blocking drugs ; exercise tachycardia ; efficacy ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effects of sotalol after oral administration were measured on the tachycardia induced by strenuous exercise in normal subjects. Plasma sotalol levels were also determined. The oral administration of sotalol (50, 100, 200 and 400 mg) to 6 subjects produced a progressive reduction in the tachycardia induced by severe exercise. This was similar to the effects of 25, 50, 100, 200, 400 and 800 mg given to different subjects. Each increase in sotalol dose produced a successively greater reduction in exercise tachycardia. This did not appear to be maximum even with 800 mg. Oral sotalol was rapidly absorbed and produced peak blood levels in 2 – 3 hours. The plasma levels of sotalol measured 2 hours after the oral administration of 25 to 800 mg showed never more than a six-fold variation between different subjects. The half-life of sotalol in plasma was 12.7 ± SE 1.6 hours. There was a significant correlation between the logarithm of the plasma sotalol concentration and the percentage reduction of exercise heart rate. It is concluded that the oral administration of sotalol either once or twice daily (depending on dose level) will provide satisfactory 24-hour blockade of β-adrenoceptors.
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  • 19
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    European journal of clinical pharmacology 9 (1976), S. 443-450 
    ISSN: 1432-1041
    Keywords: Cyclobarbital calcium ; pharmacokinetics ; plasma concentration ; relative bioavailability ; oral administration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics and relative bioavailability of cyclobarbital calcium have been studied after oral administration of Phanodorm, of tablets according to the Formularium Nederlandse Apothekers (1968; FNA), and an aqueous solution. Six healthy volunteers participated in the investigation on three occasions and each received the three preparations. The dose administered was 300 mg cyclobarbital calcium. Plasma concentrations of cyclobarbital were determined at regular intervals. Absorption from the three preparations was rapid and was faster from the solution. Peak concentrations were usually attained within 1 h. The elimination of cyclobarbital could be described by a single first-order process with an average half-life of 11.6 h (range 8 – 17 h). There was little intra-subject variation of the half-life. Relative bioavailability for each volunteer was estimated by comparing the areas under the plasma concentration curves. The FNA-tablets and Phanodorm exhibited similar bioavailability, whereas the average bioavailability of the solution was 78% of that of FNA-tablets; the reason for this unexpected finding is unknown. It was concluded that cyclobarbital cannot be regarded as a uniformly suitable drug for the treatment of insomnia. The long half-life that was apparent in some of the volunteers (15 – 17 h) creates a substantial risk of residual effects on the following morning. In principle, however, the calcium salt of cyclobarbital may be used for induction of sleep, because of its rapid absorption.
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  • 20
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    Journal of pharmacokinetics and pharmacodynamics 4 (1976), S. 199-230 
    ISSN: 1573-8744
    Keywords: disopyramide ; antiarrhythmic ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The pharmacokinetics of the antiarrhythmic disopyramide, 4-diisopropylamino-2-phenyl-2-(2-pyridyl)butyramide phosphate, and its monodealkylated metabolite were investigated in seven volunteers after intravenous (1 and 2 mg/kg) and oral (3 and 6 mg/kg) administration. Unchanged drug (52%) and the monodealkylated metabolite (25%) were renally excreted on intravenous administration. The pharmacokinetics of disopyramide were first order and dose independent only when referenced to the drug not bound to plasma proteins since this binding was dose dependent. The apparent half-lives of the α and β phases on intravenous administration were 2 min and 4.5 hr, respectively. The apparent volumes of distribution of the central and peripheral compartments, referenced to unbound disopyramide in the plasma, were 9 and 80 liters, respectively. The half-life of absorption of oral aqueous disopyramide phosphate was 30 min with a lag time of 16 min and an apparent first-pass metabolism of 16% of the absorbed dose, consistent with the hepatic efficiency of 14%. The renal and metabolic clearances were 125 and 111 ml/min, respectively. Graphical and computer analysis of the plasma and urine data showed dose-independent first-order pharmacokinetics of plasma unbound drug in a two-compartment-body model to give two metabolites and a first-pass transformation of a fraction of the oral dose. The absorption efficiency of unchanged drug was 83%.
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  • 21
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    Journal of pharmacokinetics and pharmacodynamics 4 (1976), S. 337-353 
    ISSN: 1573-8744
    Keywords: bioavailability ; pharmacological data ; pharmacokinetics ; modeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The use of data deriving from monitoring the time variation of the intensity of pharmacological effect(s) following dosing can often present an advantageous alternative to the more conventional approach of using chemical or radiological assay of blood and/or urine level data for bioavailability evaluations of drug products: bioavailability studies can be performed with drugs where no assay exists. A relatively simplified discussion of the general theoretical principles on which the use of pharmacological data is based and a stepwise description of the approach for its routine application in bioavailability studies are presented. Approaches for computing rates and extents of drug bioavailability vs. time profiles on analog and digital computers are qualitatively described and quantitatively presented in a subsequent report. The concept of preabsorption (gastrointestinal bioavailability) is introduced and biophasic availability of drugs to local sites of action is discussed.
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  • 22
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    Journal of pharmacokinetics and pharmacodynamics 4 (1976), S. 355-375 
    ISSN: 1573-8744
    Keywords: deconvolution ; bioavailability ; pharmacokinetics ; modeling ; pharmacological data
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Mathematical expressions and approaches to the computation of rates and extents of drug bioavailability for implementation on analog and digital computers are derived. The equivalency of expressions derived on the basis of assuming compartment models to an approach based on using experimentally determined weighting functions is demonstrated. The relative merits of the two techniques are discussed: their application for use with temporal pharmacological data is emphasized. The applicability of the computational techniques to determining the availability of drugs at local sites of action (biophasic availability) and to computing preabsorptive drug release into the gastrointestinal contents (gastrointestinal bioavailability) is pointed out. An approach to computationally predicting in vivo blood level or pharmacological response vs. time profiles from in vitro dissolution testing results is presented and its limitations are discussed.
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  • 23
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    Biological Mass Spectrometry 3 (1976) 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 24
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    Biological Mass Spectrometry 3 (1976), S. 1-3 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The detection of a small amount of 13C labelled methyl benzoate and its metabolites in human urine dosed 13C labelled aspirin was carried out by a new mass fragmentographic technique.
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    Biological Mass Spectrometry 3 (1976), S. 4-13 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectroscopic behaviour of the methyl ester of prostaglandins E1 and E2 has been studied with the aid of low eV spectra, measurements on metastable ion decompositions and high resolution mass measurements. Mechanisms are proposed for the formation of the majority of the abundant fragment ions of these biologically important compounds. The mass spectra of free acids are also discussed.
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  • 26
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    Biological Mass Spectrometry 3 (1976), S. 21-27 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The biological implications, the reaction possibilities and the structure of different derivatives of N-hydroxy-2-fluorenylacetamide have been described.
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  • 27
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    Topics: Chemistry and Pharmacology
    Notes: The amino acid sequence of a polypeptide can be deduced by an identification of all the dipeptides obtained from a Dipeptidylaminopeptidase I hydrolysate of the original polypeptide and its des N-terminal amino acid derivative. The components of such dipeptide mixtures can be readily identified from the chemical ionization (helium) mass spectra of their N-ethoxycarbonylpropenyl methyl ester derivatives without prior separation. The pyrolytic conversion of N-protected peptide dimethyltrideuteromethyl anilinium salts to their methyl esters in the direct insertion probe of a mass spectrometer was found to be most suitable for the derivatization of such dipeptide mixtures.
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    Biological Mass Spectrometry 3 (1976), S. 48-49 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A selective ion monitor for the Perkin-Elmer Model 270 gas chromatograph mass spectrometer is described.
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  • 29
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    Biological Mass Spectrometry 3 (1976), S. 50-50 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Biological Mass Spectrometry 3 (1976) 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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  • 31
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectral characterization of nine kinds of estrogen glucuronides was investigated. The glucuronides were analysed after conversion to n-propyl ester-O-TMS ether derivatives by gas chromatography mass spectrometry. The fragmentation of these derivatives is discussed using deuterium labels and TMS-d9 imidazole. A clear-cut difference was found between aliphatic and aromatic glucuronic acid conjugates. In particular the [M - 362]+· fragment ion was characteristic in the mass spectra of estrogen 3-glucuronides. On the other hand, four isomers of estriol and 16-epiestriol glucuronides containing an aliphatic acetal linkage were also characterized by the fragment ions of mle value 204, 345, 415 and 431 and their relative intensities. Thus, all nine estrogen glucuronides were discriminated mass spectrometrically.
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  • 32
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    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of the dimethylphosphinic, dimethylthiophosphinic and dimethylphosphinous ester derivatives of several monohydroxy steroids are reported. The fragmentations of the derivatized steroids largely depend on the nature of the the phosphorus-containing ester group. Phenolic ester derivatives exhibit the base peak at the molecular ion, whereas the spectra of the secondary phosphinic esters are dominated by very intense protonated phosphinic acid ions [Me2 P(XH)(OH)]+ at m/e 95 (X = O) or at m/e 111 (X = S). The present results also indicate the low ionization potential for the phosphinic ester group. Due to their good gas chromatographic properties, these steroid derivatives appear to be particularly suitable for gas chromatographic mass spectrometric analysis of biochemical materials.
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    Topics: Chemistry and Pharmacology
    Notes: Excellent resolution and subsequent identification of free organic acids extracted from mixed, unstimulated human saliva was obtained by gas chromatography using high resolution open tubular glass capillary columns coupled with mass spectrometry computer instrumentation. In addition to the organic acids, identified as their trimethylsilyl derivatives, the presence of 2,6-di-t-butylcresol - a food preservative - and cholesterol was established by mass spectrometry. The effects of aspirin ingestion as well as diurnal variation were studied to demonstrate the possible clinical significance of this noninvasive approach to metabolic profiling.
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  • 34
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    Biological Mass Spectrometry 3 (1976), S. v 
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  • 35
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The sterol compositions of three oceanic jellyfish have been determined using gas chromatographic mass spectrometric techniques involving the use of two separate gas chromatographic column systems. The components in overlapping peaks have been identified by comparison of the mass spectra of peaks in the two column systems using subtractive techniques. A mid-water animal, Periphylla periphylla, was found to contain a very complex and unusual sterol profile including rare 5α-stanols, whereas two other oceanic jellyfish Pelagia noctiluca and Atolla wyvillei contained similar mixtures of Δ5 sterols to those previously isolated from coastal species.
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    Biological Mass Spectrometry 3 (1976), S. 28-31 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A general derivatization method has been developed for both primary and secondary aminoalkylphosphonic acids. Derivatization is effected by reaction with trifluoroacetic acid and trifluoroacetic acid anhydride followed by esterification using ethereal diazo-n-butane. This method can be used for microgram quantities and permits ready characterization by both gas chromatography and gas chromatography mass spectrometry. The structure of this derivative has been verified by mass spectrometry and proton magnetic resonance. Fragmentation patterns were confirmed by high resolution mass spectrometry, isotope labeling and the formation of derivative analogs.
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    Biological Mass Spectrometry 3 (1976), S. 45-47 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The measurement of diphenoxylic acid, the major metabolite of diphenoxylate, has been performed in man using a deuterium labelled internal standard and multiple ion monitoring using a gas chromatograph mass spectrometer. The determination of plasma concentrations following administration of diphenoxylate to man is described.
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    Topics: Chemistry and Pharmacology
    Notes: The methyl ester of trifluoroacetic acid was prepared by reaction with N,N′-dimethylformamide dimethylacetal and was successfully passed through a gas chromatograph. Trifluoroacetic acid was detected by the use of gas chromatography and low and high resolution gas chromatography mass spectrometry in an acidic extract of an incubation medium containing microsomes, reduced nicotinamide adenine dinucleotide phosphate, oxygen and halothane. However, trifluoroacetic acid could not be detected when nicotinamide adenine dinucleotide or oxygen was omitted from the incubation system. From these results, it was proved that halothane is oxidatively metabolized to trifluoroacetic acid by hepatic microsomes.
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    Biological Mass Spectrometry 3 (1976), S. v 
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    Biological Mass Spectrometry 3 (1976), S. v 
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  • 41
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    Topics: Chemistry and Pharmacology
    Notes: A gas chromatographic mass spectrometric method has been developed for the rapid determination of a urinary tetrasaccharide (α-D-Glc-(1 → 6)-α-D-Glc-(1 → 4)-α-D-Glc-(1 → 4)-D-Glc). The urine sample is first fractionated by gel chromatography. An appropriate internal standard is added to the pooled tri-pentasaccharide fraction. Which is then reduced, methylated and fractionated by g.c. The identification of the tetrasaccharide derivative is based on the g.c. relative retention time and the mass spectrum of the reduced permethylated tetrasccharide derivative is based on the g.c. relative retention time and the mass spectrum of the reduced permethylated tetrasaccharide. The normal excretion rate was in the range of 0.1-2.5 mg per 24 hours. Greatly increased amounts (9.4-89.6 mg 24 h-1) were found in the urine of patients with glycogen storage disease type II and type III and in one patient with unclassified muscular disease. A moderate increase (3.6-8.6 mg 24 h-1) was observed in one patient with glycogen storage disease type VI. in two patients with Duchenne muscular dystrophy and in two other patients with unclassified muscular disease.
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    Topics: Chemistry and Pharmacology
    Notes: Phenacetin, paracetamol and acetanilide can be determined in a plasma or urine sample by the use of deuterium labelled analogues. These are produced by reaction of hexadeuterioacetic anhydride with the appropriate aromatic amine. The -NHCOCD3 group is stable to hydrogen exchange below pH 8. The internal standard is added to the plasma or urine after enzymatic hydrolysis of the paracetamol conjugates and an ethyl acetate extract at pH 5 is evaporated under nitrogen and the residue derivatized with N, O-bis-(trimethylsilyl)-acetamide. An aliquot of this solution is injected into a g.c.m.s. system, and one ion characteristic of the material under study and the ion from the deuterium analogue (3 mass units greater) are monitored using a voltage switching technique. In the case of phenacetin, for example, ions at 251 and 254 are monitored. Calibration curves relating different weight ratios of the hydrogen and deuterium compounds to their respective signals from the gas chromatograph mass spectrometer are used to calculate the amount of a compound in a particular sample. These methods have been developed to study the oxidation of acetanilide to paracetamol and the de-ethylation of phenacetin to paracetamol. Preliminary results from experiments with phenacetin will be discussed.
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    Biological Mass Spectrometry 3 (1976), S. v 
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    Biological Mass Spectrometry 3 (1976), S. 196-200 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic vapors in ambient air, at or near an industrial site in Baltimore, Maryland, were collected by adsorption on a sorbent of porous polymer (Tenax GC, 35/60). The pollutants were recovered by thermal desorption and analyzed by gas-liquid chromatography mass spectrometry computer using capillary glass SCOT columns. N-Nitrosodimethylamine was identified from its mass spectrum as a constituent of the atmosphere in the areas sampled. The identification of this compound was confirmed by comparison of its mass spectrum with that of authentic N-nitrosodimethylamine; identical retention times of unknown and authentic compound on three different capillary columns were observed.
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    Biological Mass Spectrometry 3 (1976), S. 207-211 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A selected ion monitoring assay has been developed to measure plasma levels of the bronchodilator pirbuterol in animals and man. Pirbuterol is extracted from plasma with acetone + potassium carbonate and after further purification is converted to its trimethylacetyl derivative. With the use of the stable isotope labeled internal standard, pirbuterol-d9, precisions of 10% and 6% were achieved at plasma concentrations of 1 and 20 ng ml-1, respectively. The synthesis of the deuterium labeled internal standard is described.
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A quantitative mass fragmentographic method for the simultaneous determination of labeled and unlabeled propoxyphene in plasma is described. Dogs treated daily with propoxyphene-d0 were treated with a pulse dose of propoxyphene-d2 at day 20. It was found that following an initial rapid equilibrium phase levels of propoxyphene-d2 fell more rapidly than those of propoxyphene-d0. This result suggests that ‘deep’ pools of tissue bound propoxyphene exist which exchange very slowly with drug present in the central compartment. Experimental evidence is presented which demonstrates that the difference in behavior of propoxyphene-d0 and -d2 is not due to unanticipated secondary isotope effects.
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    Biological Mass Spectrometry 3 (1976), S. 226-229 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Urine from rats and sheep given single oral doses of [14C]propachlor contained 14C metabolites in which the chlorine of propachlor was replaced by a methylsulfonyl group. Methylsulfonyl-containing metabolites were also isolated from the urine of rats given an intraperitoneal dose of the cysteine conjugate of [14C]propachlor; this indicated that the methylsulfonyl-containing metabolites resulted from metabolic reactions subsequent to the mercapturic acid pathway.
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    Topics: Chemistry and Pharmacology
    Notes: The methane chemical ionization spectra of a number of tertiary and quaternary amines with a N-trideuteromethyl group show substitution of this group by methyl. The isotopic purity of the original amines was shown to be 〉 99% using ammonia as a reagent gas.
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    Topics: Chemistry and Pharmacology
    Notes: Catabolic intermediates of sodium dipropylacetate, an anticonvulsant drug, in the urine extracts of the drug-treated rats were examined by the aid of gas chromatography mass spectrometry. Eleven drug-specific peaks were estimated as unmetabolized sodium dipropylacetate, succinic acid, 2-n-propyl-3-hydroxypentanoic acid, 2-n-propyl-4-hydroxypentanoic acid, 2-n-propyl-3-oxopentanoic acid, 2-n-propyl-5-hydroxypentanoic acid, adipic acid, 2-n-propylglutaric acid, dipropylacetic acid glucuronide, propionic acid and 3-heptanone. Administration of sodium dipropylacetate with isoleucine to rats resulted in the disappearance of 2-n-propyl-3-oxopentanoic acid and a considerable decrease in 2-n-propyl-3-hydroxypentanoic acid. These data indicated that β-oxidation was involved in the metabolism of sodium dipropylacetate as well as glucuronide conjugation and ω-oxidation.
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    Biological Mass Spectrometry 3 (1976), S. v 
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    Topics: Chemistry and Pharmacology
    Notes: A sensitive method for the qualitative and semiquantitative determination of terbutaline in plasma and urine has been developed After a single oral dose of 5 mg terbutaline sulphate the drug could be analysed easily. The detection limit in plasma is less than 1 ng ml-1.
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    Topics: Chemistry and Pharmacology
    Notes: Reductive methylation (the Eschweiler-Clarke reaction) was used as a route for the synthesis of differently deuterium labelled variants of trimethylamine with the ultimate aim of preparing labelled variants of choline and acetylcholine. Combinations of unlabelled and labelled formaldehyde and formic acid yielded symmetrically labelled trimethylamines of high isotopic purity. The labelled congerers to acetylcholine and choline that were prepared subsequently provide suitable internal standards and tracers to be used in mass spectral analysis and in the evaluation of the pharmacokinetics of the parent compounds.
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    Biological Mass Spectrometry 3 (1976), S. 272-277 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using electron impact and field desorption mass spectrometry, structures are proposed for narasin and a related ionophore, A28086B, derived from fermentation. The ionic fragmentation of these compounds and their derivatives is discussed and compared with that of salinomycin, whose structure has been determined by X-ray diffraction.
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    Topics: Chemistry and Pharmacology
    Notes: A sensitive method for the simultaneous determination of bufuralol and its pharmacologically active metabolites in human plasma is described. The O-trimethylsilyl,N-trifluoroacetyl derivatives are assayed by mass fragmentography. Sensitivity is 1 ng ml-1 plasma for bufuralol and about 250 pg ml-1 for the metabolites. An alternative procedure which uses gas chromatography with electron capture detection is also described. The sensitivity of this is about 10 ng ml-1 plasma for all drug-related components.
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    Biological Mass Spectrometry 3 (1976) 
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    Topics: Chemistry and Pharmacology
    Notes: A low resolution, high sensitivity study has been made of the field desorption mass spectrum of glucagon, a 29 amino acid residue underivatized peptide. The highest molecular weight fragments observed, when spectra were taken under conditions which minimized surface reactions of the peptide on the emitter, were found to contain no more than 18 amino acid residues. The most probable fragmentation processes for ions larger than m/e 600 were the production of fragments containing 10, 11 or 12 amino acid residues.
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    Biological Mass Spectrometry 3 (1976), S. 217-225 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Through the combined use of stable isotope labeling and gas chromatographic mass spectrometric analysis, the metabolic patterns for propoxyphene have been determined in laboratory animals and man. The rat and dog eliminated propoxyphene and its metabolites principally via the bile, while the rabbit more closely resembled man in excreting the metabolic products into urine. Metabolites in rat and rabbit existed as conjugates, whereas in dog and man the metabolites were excreted as a mixture of the free and unconjugated forms. The primary route of metabolism in all species studied was N-demethylation. However, the rat and rabbit extensively hydroxylated propoxyphene and its metabolltes prior to elimination. Metabolites arising from ester hydrolysis were found in rat and man. N-acetylated products were identified in all four species. A metabolite formed from cyclization and dehydration of dinorpropoxyphene was isolated in urine and was further identified as a circulating metabolite in dog plasma.
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    Biological Mass Spectrometry 3 (1976), S. 232-234 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Gentamicin sulphate employed in therapeutics consists of a mixture of three major aminoglycoside components, the gentamicins C1, C1a and C2. In the electron impact mass spectra of these components weak parent ions may be observed but they are of no diagnostic value in the commercial mixture. Chemical ionization and field desorption spectra of individual gentamicin components and commercial mixtures are reported and discussed. Isobutane chemical ionization spectra exhibit some fragmentation, but under optimum field desorption conditions little glycosidic cleavage is observed and [M + H]+ ions dominate the spectra.
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    Biological Mass Spectrometry 3 (1976), S. 295-298 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The concentration of oestrone, oestradiol and progesterone in ovarian tissue have been determined directly by quant tative high resolution mass fragmentography without the necessity of extraction or purification. The changes in the levels of these steroids in the ovary throughout a 28 day period correlate well with those measured in plasma and also with those of the corresponding metabolites excreted in urine. Some benign ovarian tumours (cysts) have been shown to contain abnormally large amounts of progesterone.
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    Biological Mass Spectrometry 3 (1976), S. 166-171 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of peracetylated daunorubicin, N-octanoyl-, N-dodecanoyl- and N-(N'-dodecanoylglycyl)daunorubicin, and perdeuteroacetylated N-dodecanoyldaunorubicin were analyzed. Major fragmentation pathways were suggested and ion compositions were determined by high resolution measurements.
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    Topics: Chemistry and Pharmacology
    Notes: Field desorption mass spectra have been obtained for dipalmitoylphosphatidyl choline-d0, -d4 and -d9. The two latter compounds were synthesized from dimethylene-d4 choline bromide and trimethyl-d9 choline bromide, respectively. Comparison was made of spectra of these three compounds obtained at different field anode temperatures in order to establish the composition of the major cleavage, rearrangement, and association ions. At low anode heating currents (≤ 20 mA) the most intense peak is [M + 1]+ which accounts for c. one-third of the total ionization. At higher temperatures various fragmentation processes, some of which are without analogy in electron impact mass spectrometry, become more important. The presence of an intermolecular methyl transfer process has been confirmed.
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A gas chromatographic mass spectrometric method for the quantitative determination of imipramine and its N-demethylated metabolite desipramine in plasma samples at the nanogram level is reported. The method involves derivatization of the extracted drugs with trifluoroacetylimidazole, a mild derivatizing reagent. Specificity is provided by selected ion recording of the [M + H]+ ions, formed upon chemical ionization with methane as reagent gas. Quantitation is achieved by stable isotope dilution techniques, using deuterium labeled analogs, prepared by acid-catalyzed exchange, as internal standards. Data on patient samples are presented.
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    Biological Mass Spectrometry 3 (1976), S. 316-328 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phosphates and phosphoramidates related to 2-chloro-4-t-butylphenyl methyl methylphosphoramidate (crufomate) were synthesized to aid in the identification of crufomate metabolites. Deuterium labeling, metastable determinations and precise mass measurements were used to establish fragmentation pathways. Evidence was obtained for the rearrangement of an N-formyl phosphoramidate (the expected result of oxidative metabolism of N-methyl phosphoramidates) to an iminomethyl phosphate.
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    Biological Mass Spectrometry 3 (1976), S. 335-339 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metabolites of the antitumor agent, ellipticine (NSC 71795), are mainly secreted in rat bile as two conjugates of hydroxylated ellipticine. The possible involvement of an arene oxide intermediate prior to hydroxylation and conjugation has been studied using 7,9-dideutero-ellipticine and by determining the conservation of deuterium in the phenolic products. The deuterated drug was synthesized by acid catalyzed exchange and was characterized by nuclear magnetic resonance and high and low resolution mass spectrometry. Mass spectra of two conjugated metabolites from rat bile showed a mass ion at m/e 263 (singly deuterated hydroxylated ellipticine). There was no evidence for conservation of deuterium at the position of hydroxylation (m/e 264). These results indicate that the major pathway of metabolism for this cancer chemotherapeutic drug, prior to conjugation and excretion in rat bile, proceeds by aromatic hydroxylation apparently without involving an arene oxide/NIH shift mechanism.
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  • 65
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    Biological Mass Spectrometry 3 (1976) 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 66
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Endogenous tryptamine, 5-hydroxytryptamine, indoleacetic acid, 5-hydroxyindoleacetic and tryptophan have been recovered from urine and cerebro-spinal fluid by adsorption on XAD-2 resin (0.3 g). After adsorption of the sample on the resin, desorption with methanol provides a single fraction that contains all of these metabolites. The mass spectra of their pentafluoropropionyl derivatives show prominent ions at m/e 276 and 438 which are characteristic of indoles and 5-hydroxyindoles, respectively, a feature that allows the concurrent determination of all the components of each group by functional group analysis. A method has been developed to carry out single ion monitoring with the peak matching system of an Hitachi RMU-6H mass spectrometer. Identifications are based on the respective Kovats Indices and single ion monitoring of two characteristic ions per compound: tryptophan (m/e 276 and 347); tryptamine (m/e 276 and 289); indoleacetic acid (m/e 276 and 335); 5-hydroxytryptamine (m/e 438 and 451); 5-hydroxyindoleacetic acid (m/e 438 and 497). The method described illustrates the feasibility of assaying biogenic indoleamines and acidic metabolites, as well as their precursor amino acid on a single fraction in contrast to other standard fractionation methods. This is possible even if the mass spectrometer is not equipped with an alternating voltage accelerator provided that it has a peak matcher, although the lack of an alternating voltage accelerator requires two separate injections of the same sample, for quantification and identification; one for the indole profile and another for the 5-hydroxyindole profile. Both profiles can be verified by individual monitoring of the other confirmatory ions. With this method the use of a multiple ion detector would allow a simultaneous determination of all of these metabolites in one gas chromatograph mass spectrometer run.
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  • 67
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
    Notes: An improved method is described for measuring low levels of prostaglandin F2α in small volumes of cerebrospinal fluid. Single ion monitoring of the ion at m/e 423. derived from the methyl ester tri-TMS ether derivatives of prostaglandin F2α and the internal standard, ω-trinor-16-cyclohexyl prostaglandin F2α, is employed. Injection of 2 pg of prostaglandin F2α derivative gave a standard deviation of ±9%. The majority of patients had cerebrospinal fluid levels of up to 2 ng ml-1 of prostaglandin. F2α, whereas in certain neurological conditions with progressive disease, elevated levels were encountered, some of which were higher than 10 ng ml-1.
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    Biological Mass Spectrometry 3 (1976), S. 122-126 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Trimethylsilyl derivatives of 1-hexadecyl-2-decanoyl-, -hexadecanoyl- and -octadecenoylglycerols and 1-octadecyl-2-decanoyl-, -hexadecanoyl- and -octadecenoylglycerols as well as 1,2-dihexadecanoylglycerol were analysed by a gas chromatograph mass spectrometer system. The following points are characteristic of the fragmentation pattern of these 1-alkyl-2-acyl derivatives: (1) in the spectra of alkyl acyl derivatives, ions at [M - 15]+ and [M - 90]+· are 14 mass units less than those of the corresponding diacyl derivatives; (2) the base peak is m/e 130; (3) alkyl acyl derivatives show fragments due to one acyl group instead of the two acyl groups of diacyl derivatives; (4) ions at m/e 314 and 342, [R10 + 73]+·, are characteristic of the trimethylsilyl derivatives of hexadecyl- and octadecylglycerols, respectively; (5) the ion [M - R10]+ is present, but the complementary alkoxy ion is absent.
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    Biological Mass Spectrometry 3 (1976), S. 137-139 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Six major components of a mixture of the pyrolysis products of deoxyribonucleic acid have been analysed by combined low energy electron impact and collisional activation spectra. The method allowed the assignment of the structures of the different components in the complex mixture without prior separation.
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    Biological Mass Spectrometry 3 (1976), S. 146-148 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α,α,β,β-d4-Serotonin (94% d4, 6% d3) has been synthesized for use as an internal standard in mass spectrometric determinations of serotonin in biological systems.
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    Biological Mass Spectrometry 3 (1976), S. 149-150 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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  • 72
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    Topics: Chemistry and Pharmacology
    Notes: Correlations between mass spectra and pharmacological activities were surveyed by means of computerized learning machine and cluster analysis. The principal component analysis and the nonlinear mapping techniques were used for the feature selection of the data set.
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    Biological Mass Spectrometry 3 (1976), S. 191-195 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The terminal amino group of amino acids and peptides is blocked as the N-succinyl derivative by reaction with succinic anhydride. The product is then converted to the N,O-permethyl derivative in order to increase its volatility for use in mass spectrometry. The permethylated N-succinyl derivative retains the advantages of the permethylated N-acetyl derivative in regard to ease of preparation on a small scale, volatility and the presence of characteristic fragmentation patterns in their mass spectra. However, peaks in the high mass region are more abundant due to loss of CH3O· from the N-succinyl carbomethoxyl group as well as from the C-terminal carbomethoxyl group. Ions characteristic of the sequence and of individual amino acids are observed, and molecular weight can be determined from the relatively abundant ion at [M — CH3O]+ and from the weak molecular ion.
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    Topics: Chemistry and Pharmacology
    Notes: The use of the mass spectrometric integrated ion current technique for the quantitative analysis of some trace metals at their tetraphenylporphyrin chelates is described. The linearity of the calibration curves and the sensitivity of the technique are improved by employing deuterated tetraphenylporphyrin chelates as loading agents. Femtomole quantities of the chelates may be detected. The use of deuterated tetraphenylporphyrin chelates as internal standards overcomes the problems of losses occurring during chromatographic separation and by thermal decomposition in the mass spectrometer.
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    Biological Mass Spectrometry 3 (1976), S. 88-90 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Isomeric chlorinated biphenyls are observed to yield very similar mass spectra, rarely exhibiting a [M — Cl]+ fragment of any siVgnificant magnitude. However, those isomers containing three ortho chloro substituents display a relatively intense [M — Cl]+ fragment. A rationalization for this observation is put forth on the basis of the relative stabilities of both product and reactant.
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  • 76
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    Topics: Chemistry and Pharmacology
    Notes: The metabolism of 5-(4′-chloro-n-butyl)picolinic acid, which inhibits dopamine β-hydroxylase and exhibits an antihypertensive effect, has been studied by gas chromatography mass spectrometry, utilising characteristic reaction products after derivatization. In rat urine five metabolites were identified by mass spectral analysis. It is found that four were elongated by a C2 unit in the carboxyl group at the 2-position on the pyridine ring and accounted for approximately 50% of the radioactivity in the 24 hour urine. The facts show that the metabolic pathway corresponding to the chain elongation of fatty acids is the major route of metabolism for this drug in the rat. Furthermore, this pathway would be confirmed in man, rabbit, guinea pig and mouse.
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  • 77
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    Topics: Chemistry and Pharmacology
    Notes: The electron impact and the hydrogen and methane chemical ionization mass spectra of 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxanilide, the sulfoxide and sulfone derived therefrom, and 2-(2-hydroxyethylthio)-acetoacetanilide enol have been determined. All four compounds show abundant molecular ions in the electron impact spectra and abundant [MH]+ ions in the methane chemical ionization spectra (along with the expected [M + C2H5]+ and [M + C3H5]+ ions), but relatively low [MH]+ ion signals in the hydrogen chemical ionization spectra. From high resolution mass measurements and metastable transitions determined by metastable ion refocusing, electron impact fragmentation mechanisms have been established. For 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxanilide, 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxanilide-4-oxide and 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxanilide-4,4-dioxide the major fragmentation mode involves loss of the anilino radical from [M]+, followed by loss of C2H4. Fragmentation to form the aniline molecular ion increases in importance with increasing oxidation state of the sulfur. In the chemical ionization of these three compounds fragmentation of [MH]+ proceeds in a similar fashion by loss of neutral aniline and by formation of protonated aniline. The electron impact mass spectrum of 2-(2-hydroxyethylthio)acetoacetanilide is dominated by the molecular ion and the aniline molecular ion. However, in the chemical ionization mass spectra characteristic fragment ions involving loss of water and loss of aniline from [MH]+, as well as protonated aniline, are observed and serve to characterize the compound.
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    Biological Mass Spectrometry 3 (1976) 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Biological Mass Spectrometry 3 (1976), S. 261-264 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyunsaturated fatty acids of human serum were analysed by combination gas-liquid chromatography and chemical ionization mass spectrometry, using isobutane as the reagent gas. The method described yielded the molecular ion of long chain unsaturated fatty acids as the base peak; these were weak or unobservable in the corresponding electron impact mass spectra. In the chemical ionization mass spectromtery, the derivatization with trimethylsilyl ether was demonstrated to be useful for the location of the double bonds of unsaturated fatty acids. Applied to the serum polyunsaturated fatty acids, these methods have given identification of C18:4, C20:4, C20:5, C22:4, C22:5ω-6, C22:5ω-3, and C22:6.
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    Biological Mass Spectrometry 3 (1976), S. 278-280 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron impact fragmentation of 1, 2-O-isopropylidene-α-D-glycero-tetros-3-ulofuranose has been studied with the help of deuterium and 18O labelling. The effect of substituting a hydrogen atom of C-4 for a CH3· radical and that of replacing the carbonyl function with a cyanomethylenic substituent is also reported.
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    Biological Mass Spectrometry 3 (1976), S. 265-271 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of linear regression analysis for the reduction of isotope dilution data is reviewed. The calculation of linear regression statistics is based upon four assumptions: zero variance in the independent variable, equal variance for all values of the dependent variable, linearity and continuity. Unfortunately, isotope dilution data often violate one or more of these assumptions, which results in the calculation of an inaccurate calibration line. The inaccuracies can be avoided through careful inspection of the data, including analyses of variance and linearity. Large differences in the variances of the dependent variable require the use of a weighted linear regression. Nonlinearity necessitates either discarding data in the nonlinear portion of the calibration or the calculation and use of atom % excess and dilution instead of the simple isotope ratios.
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    Biological Mass Spectrometry 3 (1976), S. v 
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    Biological Mass Spectrometry 3 (1976), S. 340-345 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The apparent discrepancy between theory and experimental practices in field desorption mass spectrometry has encouraged a study attempting to focus theoretical concepts more clearly into forms recognizable to the chemical investigator. Preliminary results indicate that best anode temperature for many compounds is independent of the applied voltage throughout the range available on the Varian MAT CH-5 double focusing mass spectrometer with the electron impact-field ionization-field desorption combined source. Studies of mass transfer indicate that desorption of the sample at the best anode temperature occurs in the absence of the applied field and at a rate which is indistinguishable from the rate of desorption in the presence of the field. These results and other observations, have led us to postulate a new mechanism of ion formation, involving chemical attachment reactions in a thin fluidized system. Clearly, the role of the field in this technique must be the subject of continued study.
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    Biological Mass Spectrometry 3 (1976), S. 81-87 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thirty-six Δ5- and 5α-3β-hydroxysteroids have been oxidized with cholesterol oxidase to give the corresponding Δ4- and 5α-3-ketosteroids, respectively. The mass spectral characteristics of the products (or their trimethylsilyl ether derivatives, in the case of 3-keto-hydroxysteroids) varied considerably, depending especially on the nature of the C-17 sidechain. The ion of m/e 124 (or its equivalent) from cleavage of ring B was frequently a major fragment from Δ4-3-ketosteroids, but in some instances was of insignificant abundance. Trimethylsilylation of the product of the oxidation of neoergosterol gave neoergosterone enol-trimethylsilyl ether. Fragmentations of the sidechain oredominated in the mass spectra of the 5α-3-ketosteroids.
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    Biological Mass Spectrometry 3 (1976), S. 97-99 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
    Notes: Gas chromatographic analysis of the products of reaction of diazomethane with tolbutamide and chlorpropamide indicates the formation of three compounds in both cases. As expected, N-methylation (at sulfonamide nitrogen) is the predominant reaction; minor amounts of O-methylated product are also observed. The third product in both cases is the N-methylsulfonamide formed by decomposition of the N-methylated sulfonylurea during gas chromatography. Electron impact and chemical ionization mass spectrometric analysis, as well as 1H nuclear magnetic resonance examination of samples collected from gas chromatography, confirm the structural assignments. Additionally, proton magnetic resonance analysis of the crude reaction products established that N-methylsulfonamides are not formed in the course of the diazomethane reaction and that the O-methylated derivatives are true products of the reaction. The use of a paramagnetic shift reagent allowed direct estimation of the ratios of N- to O-methylation, and the demonstration that these ratios are not vitiated during gas chromatographic analysis.
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    Biological Mass Spectrometry 3 (1976), S. 127-136 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectroscopic behaviour of prostaglandin F2α and its methyl ester has been studied. Mechanisms are suggested for the formation of the prominent ions in the spectra of these compounds. The proposed fragmentation pathways have been confirmed with the aid of low electron voltage spectra, measurements on metastable ion decompositions, high resolution mass measurements and deuterium labelling.
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    Biological Mass Spectrometry 3 (1976), S. v 
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    Biological Mass Spectrometry 3 (1976) 
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    Biological Mass Spectrometry 3 (1976), S. 155-160 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The β, γ and δ isomers of bilirubin-IX show a decreased stability as compared with the IXα isomer; characteristic mass spectra are obtained only for the tetrakis-(trimethylsilyl) derivatives of the IXα and IXγ isomers. Hydrogenation of the vinyl substituents increases the thermal stability of the bilirubins and gives rise to a characteristic mass spectrum for the tetrakis-(trimethylsilyl) derivative of meso-bilirubin-IXδ. The ethyl anthranilate azopigments derived from the four bilirubins yield characteristic mass spectra, except for the two unstable divinyl substituted azodipyrroles (mol.wt. 416), derived from bilirubin-IXβ and IXδ. The corresponding mol.wt. 420 azopigments derived from the hydrogenated bilirubins are thermally stable. Elucidation of mass spectral fragmentation pathways is facilitated by the varying positions of the substituents and by deuterium labelling, and permits the assignment of structures to the various isomeric azodipyrroles.
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    Topics: Chemistry and Pharmacology
    Notes: The electron impact and chemical ionization (isobutane) mass spectra of the TMS derivatives of 20-hydroxy-5α-pregnan-3-ones and 20-hydroxy-4-pregnen-3-ones include ions [M — 44]+· attributable to loss of a CH3CHO fragment from C-17 with migration of the TMS group to the charge-retaining fragment. Mass spectra of isotopically labelled ([3-18O], [20-18O] and [2H9-TMS]) analogues are consistent with this mechanism; [2H9-TMS] labelling further indicates that subsequent loss of a methyl group from [M — 44]+· ions does not involve the TMS group. Corresponding ions are not observed at significant abundance in the spectra of 20β-trimethyl-silyloxy-5α-pregnane and 20β-trimethylsilyloxy-4-pregnen-3-one 3-O-methyloxime. In the electron impact mass spectrum of the t-butyldimethylsilyl ether of 20β-hydroxy-4-pregnen-3-one, an ion is observed corresponding to loss of 44 atomic mass units from the intense [M — C4H9]- ion.
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    Biological Mass Spectrometry 3 (1976), S. 177-183 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fragmentation reactions of the biologically important N6-(3-methyl-2-butenyl)adenyl moiety have been re-examined with the aid of systematic deuterium labeling in the sidechain and by examination of the 1- and 7-deazanucleoside analogs. It is concluded that the diagnostic reactions which involve expulsion of C3H7 proceed predominantly by ring closure from the sidechain double bond to N-1 (ion a). Base-containing ions m/e 135 and 148 were confirmed to arise mainly by rearrangement of hydrogen from the methyl terminus to N6 and simple cleavage, respectively, but with significant contribution from other pathways involving transfer of sidechain hydrogens to the base.
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    Biological Mass Spectrometry 3 (1976), S. v 
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two methods are described for the determination of salbutamol in human plasma. The drug is extracted from the plasma as a salbutamol tetraphenylboron ion pair and determined by gas chromatography mass spectrometry. Trideuterio-salbutamol is used as an internal standard. In the first method an extensive purification procedure is used to separate salbutamol from plasma cholesterol which interferes in the assay. Salbutamol is then determined as its TMS-ether using a multiple ion recording technique to measure the intensity of the fragment ion m/e 369 and the ion m/e 372 from the TMS ether of trideuterio-salbutamol. The second method is based on the ion pair extraction of salbutamol into heptan-3-one and its determination by gas chromatography mass spectrometry as the t-butyldimethylsilyl ether. The base peak in the mass spectrum of the t-butyldimethylsilyl-salbutamol is ion of m/e 495, which is of sufficiently high mass to distinguish it from any of the ions which arise from t butyldimethylsilyl-cholesterol. Six replicate analyses of plasma samples containing 1 ng salbutamol ml-1 were carried out using both methods. When the first method was used the mean value obtained was 1.3 ng ml-1 and the coefficient of variation was 17.7%. When the second method was used the mean value obtained was 0.95 ng ml-1 and the coefficient of variation was 10%. The second method is more rapid and therefore preferable for use in clinical pharmacological studies. This method has been used to determine the plasma salbutamol concentrations at varying times after either a 4mg oral or a 200 μg intravenous dose of salbutamol to man.
    Additional Material: 5 Ill.
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  • 95
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 241-244 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction products of trifluoroacetic anhydride with peptide amides are identified as stable heterocyclic imidazolin-5(4)-ones, which can be analysed by gas chromatography mass spectrometry. The mass spectra show intense molecular ions and allow the assignment of the amino acid sequence.
    Additional Material: 2 Ill.
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  • 96
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 245-247 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Field desorption mass spectra of methotrexate and folic acid analogs yield abundant molecular or quasimolecular ions. At emitter currents above the best anode temperature, fragment ions which are useful as further confirmations of structures are observed.
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  • 97
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The identification of a number of metabolites of the novel antiarrhythmic agent, α,α-dimethyl-4-(α,α,β,β-tetrafiuorophenethyl)benzylamine (MK-251), is presented. The compound is extensively metabolized by dog, monkey, baboon and man. Similar metabolic profiles were obtained for all species. Isolation and purification were accomplished by solvent extraction and chromatographic (column, gas and thin-layer) procedures. Gas chromatography, derivatization, infrared, nuclear magnetic resonance and particularly combined gas chromatography low and high resolution mass spectrometry techniques were employed to characterize the metabolites. The major urinary and plasma metabolites were identified as 2-[4-(α,α,β,β-tetrafluorophenethyl)phenyl]-2-propanol and its glucuronide conjugate. Other metabolites characterized were: the N-glucuronide of MK-251; 2-[4-(α,α,β,β-tetrafluorophenethyl)phenyl]propene; 2-nitro-2-[4-(α,α,β,β-tetrafluorophenethyl)phenyl]propane; α,α,β,β-dimethyl-4-(α,α,β,β-tetrafluorophenethyl)benzyl methyl ether; and 4-(α,α,β,β-tetrafluorophenethyl)acetophenone. The O-methyl ether metabolite represents the first instance of in vivo alkylation of a tertiary alcohol. Tentative identification was made for the N-hydroxy analog of MK-251 and for the glycol analog of 2-[4-(α,α,β,β-tetrafluorophenethyl)phenyl]-2-propanol. The observed pharmacological response appears to result mainly from MK-251 and not from the four metabolites.
    Additional Material: 2 Ill.
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  • 98
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Twenty-five metabolites were isolated from the urine, feces or plasma of sheep given single oral doses of [14C]crufomate (4-t-butyl-2-chlorophenyl methyl methylphosphoramidate). These metabolites resulted from one or more of the following transformations: oxidation of a methyl group in the t-butyl moiety to yield either an alcohol or a carboxylic acid; hydrolysis of the phosphate and phosphoramidate bonds; oxidation of the N-methyl group to yield N-formyl phosphoramidates; methylation of the N-formyl group to yield N-methyl-N formthyl phosphoramidates; oxidative N-demethylation; conjugation with glucuronic acid. No ring-hydroxylation or dechlorination was observed, and no crufomate was isolated from the urine, feces or plasma.
    Additional Material: 2 Ill.
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  • 99
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Seven sheep metabolites of crufomate (4-t-butyl-2-chlorophenyl methyl methylphosphoramidate) were characterized as glucuronide conjugates by interpretation of mass spectral data obtained from the pertrimethylsilyl derivatives and the trimethylsilyl derivatives of the methyl esters.
    Additional Material: 6 Tab.
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  • 100
    ISSN: 1573-8744
    Keywords: pharmacokinetics ; compartmental model ; phenol red ; phenol red glucuronide ; dogfish (Squalus acanthias)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A flow-limited multicompartment model simulates the distribution and disposition of phenol red in the dogfish after intravenous administration. Glucuronide conjugate, as well as parent compound, was found in urine and bile, but not in plasma, kidney, or liver tissue. An apparent 4-hr lag in phenol red appearance in the gall bladder was simulated using two stirred tanks connected in series to represent the bile ducts. The model should facilitate use of the dogfish in pharmacokinetic studies of drugs, environmental contaminants, and other xenobiotics.
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