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  • 1
    Electronic Resource
    Electronic Resource
    Vapor-programmed thin-layer chromatography, a technique for improved separations (1968)
    s.l. : American Chemical Society
    Analytical chemistry 40 (1968), S. 2134-2138 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac50158a037
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  • 2
    Electronic Resource
    Electronic Resource
    Vapor-programmed preparative thin-layer chromatography, a technique with improved resolving power (1970)
    s.l. : American Chemical Society
    Analytical chemistry 42 (1970), S. 90-93 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac60283a027
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  • 3
    Electronic Resource
    Electronic Resource
    Development of a Radioreceptor Assay for the D2-Selective Dopamine Agonist N-0437 (1988)
    Springer
    Pharmaceutical research 5 (1988), S. 283-287 
    Details
    ISSN: 1573-904X
    Keywords: radioreceptor assay ; dopamine receptors ; bioanalysis ; N-0437 ; dopamine agonist
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract N-0437 is a recently developed dopamine (D2) agonist, theoretically attractive in the therapy of Parkinson's disease and glaucoma. Since its high potency allows small doses of the compound in clinical use and as extensive metabolism occurs in animals, a highly sensitive assay method was required for drug-monitoring purposes. To this end we developed a radioreceptor assay (RRA), a sensitive tool for the assessment of the sample's (dopaminergic) bioactivity. The RRA is based on competition between N-0437 and its tritium-labeled analogue for binding to dopamine receptors. The assay has been optimized for the preparation of the receptor suspension and the incubation conditions. Direct application of the assay for biological samples was impossible because of matrix interferences. Therefore, a solid-phase extraction method was developed in which the combination of a polar Si column and dichloromethane as eluent resulted in an effective elimination of the interferences. Recoveries were better than 90 and 95% for plasma and urine, respectively, even at concentrations at the determination limit of the method (300 pg/ml). Relative standard deviations were less than 15%. Because RRAs are stereoselective, the method discriminates between active and inactive species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1015922619831
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  • 4
    Electronic Resource
    Electronic Resource
    Unusual Reduction of the In Vitro Skin Permeation of [3H]dexetimide by Atropine (1998)
    Springer
    Pharmaceutical research 15 (1998), S. 145-148 
    Details
    ISSN: 1573-904X
    Keywords: Anticholinergics ; atropine ; [3H]dexetimide ; in vitro permeation ; transdermal delivery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1011977509931
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  • 5
    Electronic Resource
    Electronic Resource
    Determination of the enantiomeric purity of (--) 2-(N-propyl-n-2-thienylethylamino)-5-hydroxytetralin (n-0923) by chiral stationary phase HPLC (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 62-64 
    Details
    ISSN: 0899-0042
    Keywords: dopamine agonist ; direct chiral separation ; cellulose carbamate stationary phase ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The determination of the enantiomeric impurity, i.e., the percentage of (+) N-0437 (= N-0924) in several batches of (--) N-0437 (= N-0923) by chiral HPLC is described. Enantiomeric impurities were calculated based on the peak areas of the two baseline separated enantiomers in the chromatogram. The enantiomeric impurities found in different batches ranged from 0.02% to 0.11%. Calibration curves of the two isomers of N-0437 (Fig. 1,) were made twice to study the reproducibility and linearity of the method. The absorbance ratio, N-0923/N-0924, was found to be 1.02 with a relative standard deviation (RSD) of 9% over the whole concentration range used for the calibration curves.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040113
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  • 6
    Electronic Resource
    Electronic Resource
    The influence of solute structure, temperature, and eluent composition on the chiral separation of 21 aminotetralins on a cellulose tris-3,5-dimethylcarbamate stationary phase in high-performance liquid chromatography (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 389-394 
    Details
    ISSN: 0899-0042
    Keywords: chiral stationary phase ; CHIRALCEL OD ; temperature effect ; enantiomeric separation ; aminotetralins ; dopamine agonists ; resolution ; chiral recognition mechanism ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the present study 21 different chiral aminotetralins were used to investigate the mechanism behind their enantiomeric resolution (Rs) on a commercially available high-performance liquid chromatography (HPLC) cellulose tris-3,5-dimethylcarbamate stationary phase. The differences in the chemical structures of the aminotetralins used were never directly located on the chiral carbon. Their chromatographic behavior was studied for two eluent compositions at six different temperatures. Hydrogen bonding and π—π interactions are two possible solute-chiral stationary phase (CSP) interactions. Differences between the enantiomers in their spatial arrangement of positions involved in solute-CSP interactions were the major forces behind enantiomeric separation.Lowering the temperature increased the Rs for the aminotetralins having π-electrons not directly bonded to that part of the molecule where the hydrogen bonding with the CSP is located. Primary amines and secondary amines, with a sufficiently short N-alkyl substituent, showed a decrease of Rs with lower temperatures, all other aminotetralins yielding an increase of Rs with lower temperatures. © 1992 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040610
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  • 7
    Electronic Resource
    Electronic Resource
    Comparison between cellulose and amylose tris(3,5-dimethylphenylcarbamate) chiral stationary phases for enantiomeric separation of 17 amidotetralins (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 5 (1993), S. 545-553 
    Details
    ISSN: 0899-0042
    Keywords: cellulose ; amylose ; silica gel ; high performance liquid chromatography ; direct separations ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Direct enantiomeric separations of 17 chiral amidotetralins by means of high performance liquid chromatography were performed on stationary phases composed of tris(3,5-dimethylphenylcarbamate) derivatives of cellulose and amylose, coated on silica gel. The enantiomers of 15 out of 17 amidotetralins were resolved with a resolution of more than 1.5 by at least one of the chiral stationary phases. The stationary phases showed complementary results with regard to the separation of the amidotetralins, that is, pairs that did not separate on the cellulose-type column were well separated on the amylose-type column, and vice versa. There was no significant correlation between the chromatographic properties of the chiral stationary phases. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530050711
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  • 8
    Electronic Resource
    Electronic Resource
    Impact of substituents on the enantioseparation of racemic 2-amidotetralins on polysaccharide stationary phases. I. chiralcel OD (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 8 (1996), S. 574-578 
    Details
    ISSN: 0899-0042
    Keywords: enantiomers ; structural related compounds ; chiral HPLC ; cellulose ; chiral recognition mechanism ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The direct enantiomeric separation of 32 racemic 2-amidotetralins on the commercially available tris-(3,5-dimethylphenylcarbamate) derivative of cellulose, coated on silica gel (Chiralcel OD), is presented. To date, the selection of a column for the chiral separation of a racemic mixture is done empirically. Studying the impact of small changes in the chemical structure of a series of amidotetralins on the separation behavior may help to give an insight in the chiral recognition mechanism. The amidotetralins differed structurally in three of their substituents, which were never directly located on the chiral carbon atom. The enantiomers of 24 out of 32 amidotetralins could be resolved with a resolution 〉1.5. Hydrogen bonding and π-π interactions are supposed to be the major analyte-chiral stationary phase (CSP) interactions. However, the spatial arrangement of the enantiomers may play an important role too. Increasing the bulkiness of the acyl substituent led to an increase in the resolution (RS), whereas a more bulky substituent on the aromatic ring resulted in a very low resolution. The introduction of a chlorine atom into the acyl substituent additionally increased the resolving power. Chirality 8:574-578, 1996. © 1997 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Different Behavior Toward Muscarinic Receptor Binding Between Quaternary Anticholinergics and Their Tertiary Analogues (1986)
    Springer
    Pharmaceutical research 3 (1986), S. 327-332 
    Details
    ISSN: 1573-904X
    Keywords: Muscarinic receptors ; calf brain ; anticholinergics ; heterogeneity ; receptor interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A number of corresponding tertiary and quaternary anticholinergic analogues were examined for their ability to inhibit specific 3H-dexetimide binding to calf brain muscarinic receptors. In all cases the tertiary antagonists (except pirenzepine) showed steep and monophasic inhibition curves, whereas those of the quaternary derivatives were shallow (thiazinamium, methylbenactyzine) or even biphasic (oxyphenonium, methylatropine, methylscopolamine). These observations show that the addition of a methyl group to the nitrogen atom changes the mode of interaction of the anticholinergics to muscarinic receptor binding sites. Whether there are separate binding sites present or differences in interaction mode for only the quaternary moiety is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016379806395
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  • 10
    Electronic Resource
    Electronic Resource
    Disposition and Metabolic Profiling of the Penetration Enhancer Azone. I. In Vivo Studies: Urinary Profiles of Hamster, Rat, Monkey, and Man (1990)
    Springer
    Pharmaceutical research 7 (1990), S. 496-499 
    Details
    ISSN: 1573-904X
    Keywords: Azone ; disposition ; laurocapram ; metabolic profiling, man, monkey, hamster, rat ; penetration enhancers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Chain-labeled 14C-Azone was intravenously administered to hamster, monkey, and rat, to compare its metabolic profile with that obtained previously in humans after dermal application. Azone-derived radioactivity was excreted predominantly in the urine for both hamster and monkey, which is similar to the disposition in humans. Metabolic profiling in urine revealed extensive systemic metabolism to occur in all species studied. The main fraction of the metabolites was most polar in man, followed by rat, monkey, and hamster. Traces of the parent compound were detectable only in hamster urine. Although some of the polar major human metabolites were also present in rat urine, the animals were unsuitable for collecting metabolites of Azone observed in humans. In rats, complete cleavage of the dodecyl side chain was ruled out by administering Azone that had been labeled at two distinct positions of the molecule. Additionally, oral administration of Azone to rats resulted in the same metabolic profile as intravenous administration, indicating that gastrointestinal metabolism does not occur or is similar to systemic metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1015864632474
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