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  • Articles  (33)
  • 42.80  (17)
  • bioavailability
  • Springer  (33)
  • EDP Sciences
  • Inter-Research
  • 1985-1989
  • 1980-1984  (33)
  • 1940-1944
  • 1980  (33)
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  • Articles  (33)
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Keywords
Publisher
  • Springer  (33)
  • EDP Sciences
  • Inter-Research
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  • 1985-1989
  • 1980-1984  (33)
  • 1940-1944
Year
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  • 1
    Electronic Resource
    Electronic Resource
    Generation of tunable picosecond light pulses covering the frequency range between 2700 and 32,000 cm−1 (1980)
    Springer
    Applied physics 23 (1980), S. 113-119 
    Details
    ISSN: 1432-0630
    Keywords: 42.65 ; 42.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The travelling-wave parametric process allows the generation of intense picosecond pulses tunable between 2700 and 17,000 cm−1. Angle- and temperature tuning was investigated using LiNbO3 crystals of different cuts. Various factors determining the bandwidth of the new pulses are evaluated and experimental spectra are presented. Frequency doubling readily leads to light pulses up to 32,000 cm−1. The jitter of two parametric systems operating in parallel is less than 1 ps for pump pulses of 7 ps.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00899704
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  • 2
    Electronic Resource
    Electronic Resource
    Quasi-optics of the group delay of guided magnetic waves (1980)
    Springer
    Applied physics 23 (1980), S. 141-147 
    Details
    ISSN: 1432-0630
    Keywords: 42.10 ; 85.70 ; 42.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The wave-packet of a magnetic wave on reflection at an interface between a ferrimagnetic medium and free space is shown to undergo no lateral shift but only a time delay. The time delay introduced on reflection is included to obtain a quasi-optical description for the group delay of a magnetic wave guided by a planar slab of ferrimagnet in free space for the case of the magnetizations (a) normal to the surfaces of the slab, and, (b) parallel to the surfaces of the slab and to the direction of propagation. The group delay of the guided magnetic wave is caused partly by the group delay produced in the bulk of the ferrimagnet and partly by the group delay produced on reflections. The characteristics of these two contributions to the resultant group delay of the guided magnetic wave are examined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00899709
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  • 3
    Electronic Resource
    Electronic Resource
    New TEA-lasers based onD′→A′ transitions in halogen monofluoride compounds: ClF (284.4 nm), BrF (354.5 nm), IF (490.8 nm) (1980)
    Springer
    Applied physics 23 (1980), S. 283-287 
    Details
    ISSN: 1432-0630
    Keywords: 42.55 ; 42.80 ; 33
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract As an outcome of a systematic study of excitation kinetics and fluorescence spectra concerning theD′(3π2u )→A′(3π2g ) transitions in homonuclear diatomic halogens and corresponding transitions in interhalogen molecules [1], this paper describes, for the first time, TEA laser action in the three halogen monofluorides ClF, BrF, and IF. Output energies in the mJ range were demonstrated in a fast TEA discharge arrangement at the wavelengths of 284.4, 354.5, and 490.8 nm for ClF, BrF, and IF, respectively. The results suggest parameter scalability and wavelength tunability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00914912
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  • 4
    Electronic Resource
    Electronic Resource
    The influence of intrisic defects on the degradation and luminescence of GaAs and other III–V compounds (1980)
    Springer
    Applied physics 23 (1980), S. 303-309 
    Details
    ISSN: 1432-0630
    Keywords: 42.80 ; 61.70 ; 61.80 ; 78.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A significant contribution to the degradation of GaAs-based lasers and light-emitting diodes arises from the formation of so-called dark line defects. It is shown that these defects are accumulations of non-radiative recombination centres around dislocations. The centres are identified as As vacancies, which are emitted by climbing dislocations, concomitantly with the absorption of Ga interstitials. From scanning deep-level transient spectroscopy observations it is concluded that the so-called DX centres are Ga interstitials. The driving force for dislocation climb and thus for dark-line-defect formation is a supersaturation of Ga interstitials originating from the growth of the GaAs crystals under Ga-rich conditions as a consequence of the high volatility of As. Phenomena in other III–V compound semiconductors related to the formation of dark line defects in GaAs are also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00914916
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  • 5
    Electronic Resource
    Electronic Resource
    Holography with guided optical waves (1980)
    Springer
    Applied physics 21 (1980), S. 55-64 
    Details
    ISSN: 1432-0630
    Keywords: 42.30 ; 42.80 ; 42.82
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Waveguide holograms are recorded in a storage material layer covering a planar dielectric waveguide with a guided mode as reference wave. They are also read-out with a guided mode. In the storage material, assumed to have a lower refractive index than the waveguiding film, the fields of the reference and of the read-out wave are evanescent waves. We describe the preparation of the epoxy resin (Araldit) waveguides on glass substrates, their coating with a dichromated gelatin (DCG) layer as storage material, the processing of the DCG, and the recording and reconstruction techniques. Waveguide holograms of good quality with a size of several square centimeters have been realized for the first time. The holograms were recorded and read-out with wavelength λ=488 nm. They have a length of about 25 mm and a width of 17 mm. To obtain holograms that wide a special prism coupler had to be used which allowed to couple in a laser beam of elliptical cross section, and thus to excite a guided reference or read-out mode with a width of 17 mm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00886483
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  • 6
    Electronic Resource
    Electronic Resource
    Epitaxial growth of ferroelectric PLZT thin film and their optical properties (1980)
    Springer
    Applied physics 21 (1980), S. 339-343 
    Details
    ISSN: 1432-0630
    Keywords: 42.80 ; 78.20 ; 85.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A series of experiments for growing epitaxial PLZT thin films has been made with rf sputtering. X-ray and electron diffraction analyses confirm that the fabricated films grow epitaxially on SrTiO3 and MgO crystals. A good transparency in the region above 0.4 μm to infrared with good ferroelectric properties is obtained. Propagation loss of He−Ne laser light is less than 6 dB/cm, and the PLZT thin film is a promising candidate for the optical modulator and other functional elements for integrated optics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00895925
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  • 7
    Electronic Resource
    Electronic Resource
    Signal statistics of laser light scattering (1980)
    Springer
    Applied physics 21 (1980), S. 369-376 
    Details
    ISSN: 1432-0630
    Keywords: 05.40 ; 02.50 ; 42.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract After a brief survey of number fluctuations, a topic of current interest in light scattering research, the theory is developed for a particular case of this type. A laser beam of Gaussian cross section illuminates a volume in which there is a fluctuating number of identical particles. For incoherent detection the scattered intensities are additive. The interest centers on the statistics of the total scattered intensity. Starting from the moment generating function, the distribution function of scattered intensity is computed using two different methods. In an experiment designed to test the computed distributions, agreement between theory and measurement is found if the mean particle number within the scattering volume exceeds 3. The experimental procedure is described and some difficulties are explained which so far did not permit application of the theory for particle numbers much below 3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00895929
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  • 8
    Electronic Resource
    Electronic Resource
    Holography with guided optical waves (1980)
    Springer
    Applied physics 22 (1980), S. 161-170 
    Details
    ISSN: 1432-0630
    Keywords: 42.30 ; 42.80 ; 42.82
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract This paper deals with “waveguide holograms” recorded in a layer of storage material covering a planar dielectric waveguide. Reference and read-out waves are guided modes of the waveguide. Their field in the storage medium is evanescent. A theory of the diffraction efficiencies of these waveguide holograms is presented fors-polarized wavefields. To calculate the hologram structure the attenuation of the reference wave caused by absorption in the light-sensitive storage material is taken into account. Analytical expressions for the local and the overall diffraction efficiencies and for the intensity profiles of the diffracted fields are derived. The dependence of these quantities on experimental parameters (the waveguide thickness, the mode numbers of the reference and read-out waves, and the angle of incidence of the plane object wave) is presented graphically, i.e., by computer plots. Grating couplers for integrated optics can be made by waveguide holography. We consider this application to be interesting because incoupling efficiencies for Gaussian beams of up to 96% can be achieved theoretically.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00886000
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  • 9
    Electronic Resource
    Electronic Resource
    Application of pressure-tuned diode lasers to high-resolution spectroscopy (1980)
    Springer
    Applied physics 22 (1980), S. 241-243 
    Details
    ISSN: 1432-0630
    Keywords: 07.65 ; 42.55 ; 42.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The application of the high-pressure chamber with a pressure transmitting medium (liquid at room temperature) to diode-laser tuning was found to be a useful method for high-resolution spectroscopy. Ammonia absorbtion spectra in the 10 μm region were recorded with a resolution approaching the Doppler limit.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00886014
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  • 10
    Electronic Resource
    Electronic Resource
    Time averaging by means of a computer controlled dye-laser spectrometer (1980)
    Springer
    Applied physics 22 (1980), S. 361-364 
    Details
    ISSN: 1432-0630
    Keywords: 07.65 ; 42.80 ; 42.65
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The noise characteristic of available laser sources limits the sensitivity of saturated absorption spectroscopy. Time averaging is one method to improve the signal-to-noise ratio. A computer controlled dye-laser spectrometer is described which has the capability to scan several times any selected frequency range with an absolute accuracy of ±200 kHz. The sensitivity of this system is demonstrated by measuring the isotope shift of the low abundant38Ar and by detecting a weak83Kr-hyperfine component.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00901057
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  • 11
    Electronic Resource
    Electronic Resource
    Transient behaviour of pulsed dye lasers (1980)
    Springer
    Applied physics 21 (1980), S. 353-359 
    Details
    ISSN: 1432-0630
    Keywords: 42.10 ; 42.60 ; 42.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Some aspects of the transient behaviour of pulsed dye lasers are investigated both theoretically and experimentally. Relaxation oscillations induced in the output from a dye cell by an external reflector have been observed and explained, using a rate equation approximation to the physical situation in the dye cell. These oscillations are shown to play an important part in the generation of short laser pulses from long cavity dye lasers. Finally, it is proposed that 10 ps pulses can be obtained from conventional dye lasers pumped by 100 ps pulses from a high-pressure nitrogen laser.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00895927
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  • 12
    Electronic Resource
    Electronic Resource
    Towards an ideal photon correlator with a SAW-device (1980)
    Springer
    Applied physics 22 (1980), S. 113-114 
    Details
    ISSN: 1432-0630
    Keywords: 42.80 ; 85.60 ; 07
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The advantages and disadvantages of the clipped correlator for photoelectric correlation measurements are analysed. A scheme is suggested by which the problem of inversion (an inherent disadvantage of clipping) is obviated. With the availability of surface acustic wave (SAW) delay lines, we would like to point out that one can make an almost ideal photon correlator.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00897943
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  • 13
    Electronic Resource
    Electronic Resource
    Imaging properties and applications of scanning optical microscopes (1980)
    Springer
    Applied physics 22 (1980), S. 119-128 
    Details
    ISSN: 1432-0630
    Keywords: 42.30 ; 42.80 ; 72.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract This review paper is concerned with the imaging properties and major uses of scanning optical microscopes. It is shown that the confocal scanning microscope exhibits a form of super-resolution and that the instrument in general has great application in nonlinear microscopy and the inspection of electronic devices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00885994
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  • 14
    Electronic Resource
    Electronic Resource
    Borrmann-like anomalous effects in volume holography (1980)
    Springer
    Applied physics 22 (1980), S. 335-353 
    Details
    ISSN: 1432-0630
    Keywords: 42.30 ; 42.10 ; 42.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract In this review, a surgey of the evidence for the appearance in volume holography of certain anomalous effects (akin to the Borrmann effect in x-ray crystallography) is conducted, with reference to both experimental observations and theoretical models. The main part of the paper is devoted to the application of a recently-developed two-dimensional coupled-wave theory (an extension of Kogelnik's one-dimensional theory) to the modelling of such anomalous phenomena. Extensive calculations based upon this theory, for the case of Gaussian wave incidence on a uniform mixed grating for various boundary conditions, are presented in a unified two-dimensional description of Borrmann-like effects in volume holography. In particular, certain qualitative predictions of the dynamical theory of x-ray diffraction are expressed quantitatively in the two-dimensional theory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00901055
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  • 15
    Electronic Resource
    Electronic Resource
    Brewster window and windowless resonant spectrophones for intracavity operation (1980)
    Springer
    Applied physics 23 (1980), S. 319-326 
    Details
    ISSN: 1432-0630
    Keywords: 06 ; 07.65 ; 42.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract We report a new design for an acoustically resonant spectrophone well suited for intracavity operation with widely tunable lasers. Operation with Brewster angle windows or in a windowless mode is possible, and high quality factors (560 and 509, respectively) are achieved. Windowless operation permits continuous monitoring of ambient air. We discuss factors limiting the sensitivity, ∼10−7 cm−1, and present a double chopping scheme capable of significantly reducing the acoustical background encountered in windowless operation. The sensitivity of the spectrophone's performance to misalignment is also examined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00914918
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  • 16
    Electronic Resource
    Electronic Resource
    Experimental method for the measurement of hyperfine transition saturation intensities in a gaseous medium (1980)
    Springer
    Applied physics 21 (1980), S. 135-140 
    Details
    ISSN: 1432-0630
    Keywords: 35 ; 42.55 ; 42.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A saturated absorption technique, using an actively stabilized cw dye laser has been developed to measure the saturation intensities of hyperfine transitions in a gaseous medium. Hyperfine lines belonging to theB-X system of molecular iodine have been investigated. The experimental method proposed, provides a means for measurement of the absolute value of the saturation parameter of the transition with an accuracy better than 10%. The behavior of the saturation intensity of some transitions with iodine pressure has been investigated in the range 30 m Torr→90mTorr.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00900675
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  • 17
    Electronic Resource
    Electronic Resource
    Influence of the solvent matrix on the overlapping of the absorption and emission bands of solute fluorescent dyes (1980)
    Springer
    Applied physics 23 (1980), S. 369-372 
    Details
    ISSN: 1432-0630
    Keywords: 33 ; 61.40 ; 42.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract It has been observed that the separation between the absorption and the emission bands of a fluorescent dye is smaller in a rigid polymer matrix than in the liquid monomer. Low temperature measurements have been carried out in order to understand this phenomena. It has been found, that the molecular mobility of the matrix, in which the dye is dissolved, plays an important role. By doping the rigid matrix with molecules of high mobility, the separation between the absorption and emission bands can be increased. A nearly complete separation can be achieved by this doping method if the difference of the dipole moments in the ground and excited states of the dye molecules is very large. This allows, for example, to increase the brightness of the fluorescence-activated liquid-crystal display (FLAD) and the efficiency of solar collectors based on fluorescent dyes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00903218
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  • 18
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of zimelidine (1980)
    Springer
    European journal of clinical pharmacology 17 (1980), S. 111-116 
    Details
    ISSN: 1432-1041
    Keywords: zimelidine ; norzimelidine ; antidepressants ; pharmacokinetics ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The systemic availability of a new antidepressant, zimelidine, and of its pharmacologically active metabolite, norzimelidine, was studied in six healthy male volunteers. Three single doses of zimelidine (25 mg and 100 mg orally and 25 mg i.v.) and two single doses of norzimelidine (25 mg orally and i. v.) were given to each volunteer allowing at least seven days between administrations. Plasma concentrations of zimelidine and norzimelidine were determined in serial blood samples by HPLC. Following oral zimelidine peak plasma concentrations of the metabolite were attained about 3 h after dosing. Oral administration of norzimelidine itself resulted in a plasma concentration profile for this compound that was similar to that observed after oral zimelidine. Utilising the plasma concentration data following intravenous infusion of each compound, the elimination half-lives for zimelidine and norzimelidine were calculated to be 5.1 h (range 4.3–6.0) and 15.5 h (range 10.6–22.9) respectively. The total body clearances of the 2 compounds were similar at 0.52 l · min−1 (range 0.26–0.70) for zimelidine and 0.56 l · min−1 (range 0.28–0.83) for norzimelidine. The substantially longer elimination half-life of norzimelidine was apparently the result of a larger volume of distribution (9.4 l · kg−1; range 7.8–11.4) for this metabolite, as compared to zimelidine (3.21 · kg−1; range 1.6–4.9). The calculated bioavailability of zimelidine was 26% (range 9.1–39) after the 25 mg oral dose, and 29% (range 14–46) after the 100 mg dose. The bioavailability of norzimelidine was 66% (range 36–91). However, oral administration of zimelidine resulted in as much or more norzimelidine reaching the systemic circulation, as the oral administration of norzimelidine itself. This is important as a large part of the activity of the drug may be due to the metabolite.
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    URL: http://dx.doi.org/10.1007/BF00562618
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  • 19
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    Electronic Resource
    Pharmacokinetics and oral bioavailability of pyridostigmine in man (1980)
    Springer
    European journal of clinical pharmacology 18 (1980), S. 423-428 
    Details
    ISSN: 1432-1041
    Keywords: pyridostigmine ; myasthenia gravis ; pharmacokinetics ; bioavailability ; plasma levels
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of pyridostigmine was evaluated after intravenous injection in two healthy male volunteers and after oral administration to five subjects. Plasma concentrations of pyridostigmine were determined after ion pair extraction from plasma and analysis by gas chromatography — mass spectrometry with chemical ionization, using d6-pyridostigmine as internal standard. Degradation of pyridostigmine in vitro was compensated for by use of the deuterated internal standard and by rapid cooling and separation of plasma after blood sampling. After intravenous administration of pyridostigmine 2.5 mg the plasma elimination half-life was 1.52 h, the volume of distribution was 1.43 l/kg and the plasma clearance 0.65 l/kg × h. The pharmacokinetic constants were very similar after oral administration of pyridostigmine 120 mg; the elimination half-life was 1.78±0.24 h, the volume of distribution 1.64±0.29 l/kg and the plasma clearance was 0.66±0.22 l/kg × h. The bioavailability was calculated to be 7.6±2.4%. When pyridostigmine was taken together with food, the time to reach the peak plasma concentration was prolonged from 1.7 to 3.2 h. Bioavailability, however, was not influenced by concomitant food intake. “Steady-state” plasma concentrations of pyridostigmine were measured in myasthenic patients on their ordinary dose schedule of cholinesterase inhibitor drugs. More than a seven-fold difference in steady-state plasma concentration was found between patients taking approximately the same daily dose of pyridostigmine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00636797
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  • 20
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    A study of the effect of aspirin on the pharmacokinetics of oral and intravenous diclofenac sodium (1980)
    Springer
    European journal of clinical pharmacology 18 (1980), S. 415-418 
    Details
    ISSN: 1432-1041
    Keywords: diclofenac ; acetyl salicylic acid ; intravenous bolus administration ; oral administration ; interaction ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Previous studies have shown that aspirin interacts with orally administered diclofenac sodium, causing reduced peak concentrations, lower levels and decreased areas under curves. In this study, diclofenac sodium was administered orally and intravenously with and without aspirin, to 6 healthy female volunteers. After intravenous dosing both plasma levels and areas under curves were significantly reduced although none of the rate constants was affected. The volume of distribution of diclofenac was increased as was the plasma clearance. Oral administration with aspirin also resulted in lower plasma levels, particularly peak levels, and areas under curves. Comparison of AUC's for both modes of administration with and without aspirin suggested that lower levels after oral administration were not due to impaired absorption. These observations are best explained by decreased protein binding and increased biliary excretion of diclofenac in the presence of salicylate.
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    URL: http://dx.doi.org/10.1007/BF00636795
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  • 21
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    Absorption rate and bioavailability of valproic acid and its sodium salt from rectal dosage forms (1980)
    Springer
    European journal of clinical pharmacology 17 (1980), S. 309-315 
    Details
    ISSN: 1432-1041
    Keywords: valproic acid ; sodium valproate ; suppositories ; micro-enemas ; steady-state concentration ; absorption ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Rectal and oral absorption of valproic acid and its sodium salt by man were compared to explore the possibility of rectal administration of the drug. The plasma concentration of valproic acid was measured by gas chromatography after a single oral dose of sodium valproate 600 mg, and after single rectal doses of sodium valproate 600 mg and valproic acid 520 mg, in a cross-over study in 7 volunteers. The rectal dosage forms included fatty suppositories and aqueous solutions. Compared with oral administration, rectal absorption of sodium valproate from an aqueous micro-enema was fast and complete. The free acid was absorbed more rapidly from fatty suppositories than was the sodium salt. The absorption rate from the rectum increased with the dose of valproic acid. Both findings are consistent with a diffusion — absorption mechanism based on the pH-partition hypothesis. Differences in the chemical composition of the fatty suppository base were not reflected in differences in absorption rate and relative bioavailability. No essential difference in absorption rate was observed if volunteers remained lying or sitting during the experiment. Rectal dosing with valproic acid 520 mg dissolved in 4 ml suppositories, twice a day resulted in steady-state plasma concentrations of 50 to 100 µg · ml−1, within the therapeutic range.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00625806
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  • 22
    Electronic Resource
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    Disposition and clinical pharmacokinetics of microcrystalline theophylline (1980)
    Springer
    European journal of clinical pharmacology 17 (1980), S. 379-384 
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    ISSN: 1432-1041
    Keywords: theophylline ; aminophylline ; obstructive lung disease ; microcrystalline ; bioavailability ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Variation in the systemic disposition of theophylline after ingestion of a new microcrystalline product (Theolair®) has been investigated in 7 hospitalized patients with generalized obstructive lung disease. Disposition (absolute bioavailability) was determined by comparing in the same patients the areas under the serum concentration-time curves after a single oral dose of microcrystalline theophylline and after an intravenous infusion of aminophylline. Oral absorption appeared to be fast. The half-life of absorption was 19±9 min (mean±SD). Maximal serum concentrations reached after 100±30 min were found to be in a rather narrow range: 9.8±2.5 mg · 1−1. The absolute bioavailability of the microcrystalline preparation was high and it showed only small variation: 102.7±10.2% of the dose. Relevant pharmacokinetic parameters (half-life of elimination, volume of distribution and total body clearance) were determined after both routes of administration. Individual dosage regimens required to obtain a therapeutic serum concentration were calculated for each individual patient on the basis of the observed pharmacokinetic parameters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558452
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    Electronic Resource
    Electronic Resource
    Plasma concentrations of mebendazole during treatment of echinococcosis (1980)
    Springer
    European journal of clinical pharmacology 17 (1980), S. 375-378 
    Details
    ISSN: 1432-1041
    Keywords: mebendazole ; echinococcosis ; bioavailability ; absorption ; concomitant eating ; plasma level
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary High oral doses of mebendazole are used experimentally for the treatment of human alveolar and cystic echinococcosis. In order to assess bioavailability of this drug 1.5 g doses were given to 3 volunteers. Measurable plasma concentrations of 17 to 134 nmol/l were found only if mebendazole was given together with a fatty meal. In a patient with cholestasis plasma concentrations were higher than in the 3 normal subjects. In patients on long term treatment the increase in plasma concentration after administration of a 1 g dose varied between 0 and 500 nmol/l. It is concluded that systemic availability of mebendazole is enhanced by concomitant food intake. In view of the large intra- and interindividual variation in plasma concentration, monitoring plasma levels during long term therapy appears advisable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558451
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  • 24
    Electronic Resource
    Electronic Resource
    Relative bioavailability of a paracetamol suppository (1980)
    Springer
    European journal of clinical pharmacology 17 (1980), S. 465-468 
    Details
    ISSN: 1432-1041
    Keywords: paracetamol ; suppository ; tablets ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The relative bioavailability of a new paracetamol suppository (Panodil) and tablets in doses of 0.5 and 1 g was investigated in eight healthy subjects. The tablets were absorbed faster and higher peak plasma concentrations were obtained than after the suppositories. The bioavailability of the suppositories was approximately 80% of that of the tablets at both dose levels. There was no indication of capacity-limited elimination at either the two doses investigated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00570165
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  • 25
    Electronic Resource
    Electronic Resource
    Comparative bioavailability of disopyramide after multiple dosing with standard capsules and controlled-release tablets (1980)
    Springer
    European journal of clinical pharmacology 17 (1980), S. 209-213 
    Details
    ISSN: 1432-1041
    Keywords: disopyramide ; bioavailability ; controlled-release tablets ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Plasma concentrations and bioavailability of disopyramide following repeated administration of standard capsules and controlled-release tablets have been compared. Ten patients were randomized into two groups; Group I received disopyramide capsules 150 mg every 6 h for five days and subsequently disopyramide controlled-release tablets 300 mg every 12 h for further five days. Group II received the same preparations in the reverse order. There was a more rapid rise in disopyramide concentration after the capsules: the maximum of 10.7±0.6 µmol/l (mean ± SEM) was reached within 1.8±0.4 h as compared to 10.6±0.4 µmol/l within 4.0±0.3 h after the controlled-release tablets. No significant difference in the fluctuations in individual plasma concentrations during each dose interval at steady state were observed after ordinary capsules compared to controlled-release tablets. The extent of bioavailability was the same. Eight patients reported some side-effects during the capsule period and nine during the controlled-release tablet period.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00561902
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  • 26
    Electronic Resource
    Electronic Resource
    Systemic availability of orally administered L-dopa in the elderly Parkinsonian patient (1980)
    Springer
    European journal of clinical pharmacology 17 (1980), S. 215-221 
    Details
    ISSN: 1432-1041
    Keywords: L-dopa ; elderly ; pharmacokinetics ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Previous studies have suggested that the absorption of L-dopa in the elderly Parkinsonian patient might be unusually efficient. In the present investigation, the systemic availability of L-dopa was examined in 5 elderly Parkinsonian patients (mean age=77 years) and 6 young, healthy volunteers (mean age=26 years) following a single oral 300 mg dose of L-dopa. Quantitation of plasma levels of intact L-dopa was effected by ion-exchange column chromatography and spectrofluorimetry. The L-dopa plasma concentration-time profiles obtained confirmed the considerable intersubject variability in the absorption of L-dopa previously reported in the literature. Maximum plasma concentrations of L-dopa generally occurred within 60 min of administration of the dose. The existence of more than one plasma peak of L-dopa concentration was displayed in 45% of the subjects studied. This characteristic was not confined exclusively to either subject group. There was a significantly larger (P〈0.02) area under the plasma L-dopa concentration-time curve (AUC o ∞ ) in the elderly Parkinsonian patients (mean=234.69 µg · min/ml; SD=84.70) compared to the young, healthy volunteers (mean=82.33 µg · min/ml; SD=31.00). A significant (P〈0.01) correlation existed between AUC o ∞ and age (r=0.7970; n=11) among the subjects studied. The apparent elimination phase plasma half-life of L-dopa in the elderly Parkinsonian patients (mean=66.0 min; SD=11.1) was not significantly different to that observed in the young, healthy volunteers (mean=74.0 min; SD=18.1). These results suggest that there may be an age-related alteration to the disposition of orally administered L-dopa in the elderly Parkinsonian patient.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00561903
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  • 27
    Electronic Resource
    Electronic Resource
    The pharmacokinetics of intravenous and oral sulpiride in healthy human subjects (1980)
    Springer
    European journal of clinical pharmacology 17 (1980), S. 385-391 
    Details
    ISSN: 1432-1041
    Keywords: sulpiride ; pharmacokinetics ; serum clearance ; renal clearance ; bioavailability ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of sulpiride was studied in 6 healthy volunteers after intravenous and oral (tablets) administration of 100 mg. An open two- and in two subjects a three-compartment model was applied following intravenous administration. The average total distribution volume during the terminal slope was 2.72±0.66 l/kg and total systemic clearance was 415±84 ml/min. The serum half-life of the terminal slope following intravenous administration averaged 5.3 h (range 3.7–7.1 h) according to the two-compartment model. In two subjects the half-lives were 11.0 and 13.9 h when the three-compartment model was applied. Determination of urinary excretion rates of unchanged sulpiride indicated a half-life of 7.15 h. Following intravenous administration, 70±9% of the dose was recovered unchanged in urine within 36 h; the mean renal clearance was 310±91 ml/min. Sulpiride was absorbed slowly, with peak concentrations appearing between 3 and 6 h after oral administration. The recovery of unchanged drug in urine following oral administration was 15±5% of the dose, with a mean renal clearance of 223±47 ml/min. The bioavailability determined from combined plasma and urine data was only 27±9%. The low bioavailability was probably due to incomplete absorption.
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    URL: http://dx.doi.org/10.1007/BF00558453
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  • 28
    Electronic Resource
    Electronic Resource
    Enteral absorption and bioavailability in children in relation to age (1980)
    Springer
    European journal of clinical pharmacology 18 (1980), S. 43-50 
    Details
    ISSN: 1432-1041
    Keywords: enteral drug absorption ; development ; bioavailability ; neonates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary There is little information about enteral drug absorption during development compared to that about drug distribution, metabolism and excretion. Therefore, the bioavailability, i.e. the amount and rate of absorption of various drugs (sulfonamides, phenobarbital, digoxin, β-methyldigoxin) and test substances (D(+)-xylose, L(+)-arabinose) was investigated in 580 children using pharmacokinetic methods. The amounts of the drugs absorbed, determined by Dost's law of corresponding areas, showed no age dependence. But the rate of absorption, ka, calculated from the concentration time curves using a digital approximation procedure (RIP), is low at the time of birth and reaches adult values after the neonatal period. This phenomenon is identical for all of the substances tested. A prolonged gastric emptying time in the neonate does not seem to be responsible for the delayed absorption since the lagtime is not related to age. Stimulation of intestinal motility with metoclopramide increases the absorption rates, both in neonates and older children, but the age dependent differences remain. Using various dosages of L(+)-arabinose the parameters of the saturation kinetics could be determined. In neonates Vmax values are significantly lower than in older children. Similarly, the affinity constant $$\mathop K\limits^ \star$$ indicates a decreased capacity of enteral absorption in neonates compared with older children. Bioavailability data from adults cannot be accepted without further investigation since the rate of enteral drug absorption depends on age.
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    URL: http://dx.doi.org/10.1007/BF00561477
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  • 29
    Electronic Resource
    Electronic Resource
    An algorithm and computer program for deconvolution in linear pharmacokinetics (1980)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 8 (1980), S. 463-481 
    Details
    ISSN: 1573-8744
    Keywords: bioavailability ; absorption ; deconvolution ; computer program for deconvolution ; algorithm for deconvolution ; drug input evaluation ; input response in linear pharmacokinetic systems ; pentobarbital absorption ; cimetidine absorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The procedure of deconvolution to evaluate the rate and the extent of input from absorption data and data from intravenous administration is the most fundamental and least assumptive method of accurately evaluating drug absorption in linear pharmacokinetics. It is shown for linear systems that if the absorption response and the response from an intravenous infusion or bolus administration are both well approximated by a polyexponential function, then the rate of absorption can be expressed as a sum of exponentials. An algorithm and computer program are presented whereby the absorption function is uniquely defined from the model-independent parameters of the polyexponential expressions fitted to the absorption data and data from intravenous administration. Fitting a sum of exponentials to data has become a routine procedure in pharmacokinetics. The method presented therefore makes the previously complex task of deconvolution a simple procedure. The deconvolution approach is discussed in relation to conventional methods of evaluating drug absorption and appears to have some distinct advantages over these methods. The method is tested using simulated data and demonstrated using pentobarbital and cimetidine data from human subjects.
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    URL: http://dx.doi.org/10.1007/BF01059546
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  • 30
    Electronic Resource
    Electronic Resource
    Gastrointestinal absorption of quinidine from some solutions and commercial tablets (1980)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 8 (1980), S. 243-255 
    Details
    ISSN: 1573-8744
    Keywords: quinidine ; bioavailability ; absorption ; solutions ; rapidiy releasing tablets ; humans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The gastrointestinal absorption of quinidine from three commercially available tablet products has been compared to that from a quinidine sulfate solution previously found to have 70% of the systematic availability of an intravenous dose. Quinidine gluconate solution was included in the study to compare the absorption characteristics of the two quinidine salts. The tablets were given in a counterbalanced sequence preceded by one quinidine solution and followed by the other in a crossover design. The three tablets proved to be equivalent to one another with respect to extent and rate of absorption. The absorption properties of the two solutions were indistinguishable. The tablets were equivalent to the solutions in extent but not in rate of absorption.
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    URL: http://dx.doi.org/10.1007/BF01059645
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  • 31
    Electronic Resource
    Electronic Resource
    Evaluation of the absorption from some commercial enteric-release theophylline products (1980)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 8 (1980), S. 151-164 
    Details
    ISSN: 1573-8744
    Keywords: theophylline ; absorption ; bioavailability ; enteric release ; tablets ; plasma concentrations ; dissolution data
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In a single-dose bioavailability study, Wales, Robinson, Columbia, and Choledyl (Warner/Chilcott) enteric-coated tablets all allowed a bioavailability of theophylline (99%±25%, 102%±23%,103%±18%, and 98%±15%;mean±SD, n=12) statistically indistinguishable from that of the standard uncoated tablet (Searle 200 mg aminophylline). Only the Wales and Choledyl tablets (7.6, 4.2 hr) could be shown (p〈0.05) to generate a peak plasma theophylline concentration later than the standard (1.4 hr). All tablet brands demonstrated a significant lag time before appearance of theophylline in the plasma, and both Wales and Choledyl tablets also had a (t peak -t tag )statistically different from that of the standard. Despite misleading indications from the mean plasma profile (plasma concentrations at each sampling time averaged over all subjects), plasma data from the individual participants and in vitrodissolution data show that, while release of theophylline from the Wales tablet might be inordinately slow, this is not a sustained-release preparation. Of the enteric-coated tablets only the Columbia product allowed significant levels in the first sample after dosage. Five of the 18 Columbia doses gave rise to 40–99%of the peak concentration in the 1- hr sample. In vitro,it takes 39±14 min for 40% of the theophylline content of Columbia tablets to dissolve in simulated intestinal fluid. Surprisingly rapid delivery of an entericcoated tablet to the duodenum would appear to be required to allow a significant percentage of theophylline to be dissolved and absorbed before 1 hr. None of 12 Columbia tablets tested in vitro,however, allowed dissolution of more than 0.2% of their theophylline content during 1 hr immersion in simulated gastric fluid. Since once in intestinal fluid Columbia tablets appear to dissolve more rapidly than the other enteric products, it is not clear whether the five Columbia tablets in question had imperfections or whether, in fact, this tablet brand more closely than the others represents the ideal of immediate release once in the duodenum. Plasma samples should be taken as early as 15 min after dosage when evaluating the bioavailability of enteric release products.
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    URL: http://dx.doi.org/10.1007/BF01065190
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  • 32
    Electronic Resource
    Electronic Resource
    Bioavailability of microsize and ultramicrosize griseofulvin products in man (1980)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 8 (1980), S. 347-362 
    Details
    ISSN: 1573-8744
    Keywords: griseofulvin ; bioavailability ; HPLC assay ; plasma levels ; human study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The relative bioavailability of ten marketed dosage forms of griseofulvin was evaluated in two separate crossover studies. Each study utilized 12 healthy subjects, with eight of the subjects being common to both studies. Plasma griseofulvin concentrations were determined 1, 2, 3, 4, 6, 8, 10, 25, 34, 49, and 73 hr after dosing, using a high-pressure liquid chromatographic method. The “high-dose” study compared four microsize dosage forms administered as 500-mg doses and two ultramicrosize formulations given as 250-mg doses. The “low-dose” study employed four 250-mg microsize products and two 125-mg ultramicrosize products. The individual plasma level-time profiles for the majority of doses suggested prolonged absorption of microsize griseofulvin. The ultramicrosize dosage forms exhibited peak concentrations which were not significantly different (p〉0.05) from those of the microsize products administered as twice the dose. In the high-dose study, the two 250-mg ultramicrosize dosage forms exhibited areas under the plasma level-time curve (AUC) which were significantly (p〈0.05) less than the AUCs for all but one of the 500-mg microsize products. In the low-dose study the AUCs for the ultramicrosize products were significantly lower than the AUCs for all of the microsize dosage forms. Significant differences were also noted among the AUCs for the microsize products, although the maximum difference was less than 20% in both studies. A comparison of the AUCs observed in the high- and low-dose studies revealed that the AUCs for two of the 500-mg microsize dosage forms were only approximately 75% the AUC predicted from the 250-mg dose for the eight subjects common to both studies. All other formulations exhibited a dose proportionality for AUC.
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    URL: http://dx.doi.org/10.1007/BF01059383
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  • 33
    Electronic Resource
    Electronic Resource
    Evaluation of the absorption from some commercial sustained-release theophylline products (1980)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 8 (1980), S. 131-149 
    Details
    ISSN: 1573-8744
    Keywords: theophylline ; absorption ; bioavailability ; sustained release ; tablets ; plasma concentrations ; mean plasma concentrations ; steady-state projections
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Absorption of theophylline from three commercial products labeled as sustained release was compared to the absorption from a standard uncoated tablet (Searle 200-mg aminophylline tablet) in a single-dose study. Aminodur tablets (Cooper) and Slophyllin Gyrocap capsules (Dooner) had bioavailability (100.2%±19.8% and 98.5%±13.8%) statistically indistinguishable from that of the standard but showed significantly slower absorption (peak times of 10,4±2.8 and 4.36±1.35 hr) and lower peak plasma concentrations (13.9±4.5 and 22.6±3.5gmg/ml/g dose) than the standard (t peak ,1.52±0.45 hr; Cpeak,28.l±6.2μg/ml/g dose). The time of the plasma concentration peak (2.47±1.38 hr) after a dose of Tedral S.A. (Warner/Chilcott) was not statistically different from that after the standard, but both the peak concentration (16.0±3.9 gmg/ml/g dose) and bioavailability (76.0±18.4%) were. Multiple-dose projections from single-dose data indicate that of the three test products only Aminodur maintains reasonably constant interdose plasma levels during 12 hourly dosing. With an 8 hourly dosing schedule Gyrocaps also might be satisfactory. Reasonable predictions of the plasma concentrations arising from Aminodur doses have been made using a single-compartment body model and assuming input from an outer followed by an inner layer of the tablet. Typically a single dose of a preparation designed for constant release of drug over 12 hr should not produce a plasma concentration plateau in subjects with an average 6.1-hr drug half-life. The apparent plateau in the mean plasma profile (i.e., concentrations at each sampling time averaged over all subjects) for Aminodur doses is evaluated. The interpretation commonly being implied in the publication of mean profiles from bioavailability studies is misleading, particularly when applied to sustained-release preparations.
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    URL: http://dx.doi.org/10.1007/BF01065189
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