Search PubMed⌕ Search

Biomedical subjects

V Häselbarth

Publications and source records attributed to V Häselbarth.

5 recordsLinked to original sources
PubMed1985

[Statistical tests for bioequivalence].

The application of statistical tests of hypotheses in the evaluation of bioavailability studies is discussed. The necessity of correctly indicating the risk of false decisions in accordance with the hypothesis to be tested is emphasized. The procedure of evaluation presented here is performed analogously to the methods of the statistical quality control and always takes errors of the 1st kind and the 2nd kind into account. The advantageous use of the operating characteristic is pointed out. It is possible to read from these curves the effects which the size of the random sample and the experimental variation have on the reliability of the statement. The procedure is illustrated by means of numerical examples from literature.

Biological Availability↗
PubMed1981

Kinetics and bioavailability of mexiletine in healthy subjects.

Single-dose kinetics of mexiletine (MEX) was studied in six healthy subjects after three different formulations. The respective doses were 200 mg (intravenous infusion), 400 mg (two conventional capsules), and 432 mg (sustained-release dosage forms). By a three-compartment open model with lag time the kinetic parameters of the drug were calculated from the experimental plasma level data. The mathematical analysis of the processes of distribution and elimination was restricted to the intravenous data only, and the resulting transfer constants were introduced into the evaluations of the oral experiments. With this procedure one common value for the plasma t 1/2 of elimination was obtained (t 1/2 gamma = 6.34 +/- 1.5 hr). Mean values for the total volume of distribution (Vdtot) and the total body clearance (Cltot) were 5.5 l/kg and 10.3 ml/min/kg. After capsules, peak plasma concentrations (Cmax = 0.77 microgram/ml) were reached after 2.2 hr. and the sustained-release form built up a flat maximum of concentration (Cmax = 0.34 microgram/ml) after 9.2 hr. Mexiletine is highly bioavailable, almost identical for the two oral formulations: 87.3% (capsule) and 78.7% (slow release). Under physiologic urinary pH1 7.5% to 9.2% of the dose was excreted unchanged by the kidneys.

Adult↗
PubMed1976

[A quantitative gaschromatographic method for the determination of p-chlorophenoxyisobutyric acid (clofibrinic acid) in human plasma (author's transl)].

The report describes a sensitive and selective GLC-method for the plasma level estimation of p-chlorophenoxyisobutyric acid (CPIB), the biologically active metabolite of clofibrate. After addition of an internal standard substance the acid is extracted and converted to its methylester by diazomethane. Following oral administration of equimolar doses of clofibrinic acid and clofibrate (445 and 500 mg, respectively) to 4 normal volunteers plasma concentrations could be measured for 72 h. A comparison of different pharmacokinetic parameters indicated that the two compounds gave almost identical absorption profiles in respect of CPIB. CPIB disappeared from plasma with a mean half-life of 17.6 h.

Chromatography, Gas↗