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Biomedical subjects

L Vereczkey

Publications and source records attributed to L Vereczkey.

At least 73 records · Page 4Linked to original sources
PubMed1979

Metabolism of mesocarb in the rat.

1. Rats treated orally with [14C]mesocarb (I; 3-(1-methyl-2-phenyl[2-(14C]ethyl)-N-(phenylaminocarbonyl)sydnone imine) (50 mg/kg) excrete 35% of the radioactivity in 24 h urine and 51% in 48 h urine. 2. Only traces of unchanged drug were found in urine. Hydroxy-mesocarb (II), dihydroxy-mesocarb (III), amphetamine (VII) and the conjugates of II and III account for 86% of the urinary radioactivity. 3. Cannulated male rats excrete about 40% of the radioactivity in 30 h in bile, mainly as conjugates of II and III.

Amphetamine↗
PubMed1979

Kinetic metabolism of vinpocetine in the rat.

The pharmacokinetics of vinpocetine (Cavinton), a new potent vasodilator, and of its main metabolite have been studied in rats by specific extraction and radio thin-layer chromatography following i.v. and p.o. administration. The drug is rapidly eliminated, its half-life was found to be 125 min. The apparent volume of distribution was 3.8 l/kg and the clearance rate 33 ml/min/kg. From the equation describing the concentration-time curve a two-compartement open model was computed. Bioavailability of vinpocetine after p.o. administration was about 50%. The main metabolite, free apovincaminic acid, is formed very rapidly in rats and is eliminated from plasma with a half-life of 360 min.

Administration, Oral↗
PubMed1979

Pharmacokinetics of vinpocetine in humans.

The pharmacokinetics of ethyl-apovincaminate (vinpocetine, Cavinton), a new vincamine derivative has been studied in volunteers after p.o. and i.v. administration. The concentration of the drug was determined by mass-fragmentography in human plasma. There was a biphasic elimination of the substance after i.v. injection with a T1/2 alpha of 0.136 h and with a T1/2 beta of 4.83 h. The value of Vdss (2.1 l/kg) shows a high adsorption of the drug by tissue proteins. The clearance rate of elimination was 0.366 l/h/kg. Oral administration of the drug resulted in maximum plasma concentration 1--1.5 h after the administration with values of 20--62 ng/ml. The bioavailability of the drug--calculated from the ratio of the areas under the concentration-time curves--proved to be 56.6 +/- 8.9%. Unchanged vinpocetine could not be detected in urine. From the results two-compartment open models were constructed and the steady state concentrations after multiple dosing were computed.

Administration, Oral↗
PubMed1976

Gas chromatographic method for the determination of nomifensine in human plasma.

An analytical method based on solvent extraction, formation of a fluorinated derivative and quantitation by gas-liquid chromatography using an electron capture detector has been developed for the determination of nomifensine in biological fluids. The specificity (controlled by mass spectrometry) and the sensitivity appear to be satisfactory for drug level measurements in human body fluids. Its relative simplicity in fact permits its use in serial analysis.

Antidepressive Agents↗
PubMed1976

Pharmacokinetic data on tritium labelled ethyl apovincaminate.

Absorption, tissue distribution and excretion of tritium labelled ethyl apovincaminate (RGH-4405, Cavinton) were studied. Both oral and i.p. administration resulted in a relatively rapid elimination of tritium activity, suggesting that neither the original drug nor its metabolites remained in the organism of rat. 50% of radioactivity was recovered in urine and 30% in faeces during 48 h. At this time only liver and kidneys contained measurable quantities of radioactivity among the organs tested. Biliary route of elimination seemed to be important, since 20% and 4% of radioactivity appeared in bile during 9 h following i.p. and p.o. administration, respectively. Enterohepatic circulation was of no consequence. Radioactivity was hardly adsorbed to or absorbed by blood cells and was almost completely bound by plasma protein(s).

Administration, Oral↗
PubMed1976

Metabolism of ethyl apovincaminate in the rat.

Ethyl apovincaminate (RGH-4405, Cavinton) is well metabolized in rat, and only a small fraction of the original compound is excreted in urine. The main urinary metabolite is apovincaminic acid, hydrolytical product of Cavinton produced partly by plasma esterases. In plasma only the original compound and free acid are detectable. Several other metabolites have been isolated from bile and characterized by mass spectrometry. Cavinton is hydroxylated at the indole moiety and forms conjugates (possibly glucuronide and sulfate). The glycine derivative of apovincaminic acid containing two hydroxygroups has been detected in significant amounts, analysed by mass spectrometry. Among minor metabolites vincaminic acid ethyl ester has been found. More than 80% of total urinary and 50% of total biliary metabolites have been identified by radiochromatography, mass and IR spectroscopy.

Animals↗
PubMed1975

Pharmacokinetics of nomifensine in man.

Nomifensine pharmacokinetics were determined in healthy volunteers after the oral administration of 50 mg of the drug. Peak plasma levels of 95-177 ng/ml were attained within 1 to 4 hrs, and the apparent plasma half-lives ranged from 3.3 to 4.9 hrs. Assuming 100% bioavailability the drug has a relatively large apparent volume of distribution. From these findings it appears that the pharmacokinetics profile of nomifensine is considerably different from those of other known antidepressants. Implications for dosages schedules are discussed.

Administration, Oral↗