A Brandstätter | PubMed Health

PubMed2005

A study concerning the blood/breath alcohol conversion factor Q: concentration dependency and its applicability in daily routine.

The conversion factor Q, obtained by division of blood alcohol concentration (BAC) by breath alcohol concentration (BrAC) is a widely discussed topic due to its great variance. By Austrian law, regulations frequently require an estimation of a corresponding BAC by a measured BrAC. It is known that Q depends among other things, on the alcohol kinetic state of the person being tested, which mathematically can be transformed to a dependency on the BrAC. Theoretically calculated Q values per BrAC level form a hyperbola shaped curve, thus decreasing with increasing BrAC values. Applying Austrian forensic standards for BAC and BrAC measurements, these calculations were verified in a study under practical conditions with BAC and BrAC data of 390 individuals. Q decreases from 2629 (+/- 455) for BrAC levels < 0.1 mg/l to 2229 (+/- 160) for a BrAC range of 0.4-0.5 mg/l and increases again to 2428 (+/- 124) for BrAC levels > 0.6 mg/l. Since these results were obtained under realistic practical conditions they can be directly applied in routine forensic expert opinion and can eliminate avoidable variances in the calculation of Q.

Adult↗

PubMed1985

Relationship between pharmacokinetics and pharmacodynamics of molsidomine and its metabolites in humans.

The pharmacokinetic properties and hemodynamic effect of molsidomine and its pharmacologically active metabolite SIN-1 were investigated in 13 healthy volunteers following single oral doses. Hemodynamic changes were measured by finger plethysmography (peripheral arterial resistance), impedance plethysmography (venous distensibility), heart rate, and blood pressure. Plasma concentrations of molsidomine, SIN-1, and SIN-1C were measured by means of high-pressure liquid chromatography. Oral administration of rapidly dissolving tablets of molsidomine (2 tablets of 4 mg), a sustained-release form of molsidomine (8 mg), and SIN-1 (4 mg) caused an increase of the a/b ratio of the finger plethysmogram and an increase of the venous distensibility. Heart rate and blood pressure remained unaffected. The time course of the peripheral arterial effect mimicked the time course of plasma concentrations of molsidomine and SIN-1. Similar to the results in animals, molsidomine was metabolized in humans to SIN-1 and subsequently degraded to the inactive metabolite SIN-1C. The kinetic profile of both metabolites could be followed in the plasma. The rate-limiting step in the metabolic sequence of molsidomine was found to be enzymatic hydrolysis and decarboxylation of molsidomine to SIN-1. Concentration-response curves of the a/b ratio of the finger plethysmogram showed that the plasma concentrations required to produce a definite effect are much higher for molsidomine than for SIN-1. This shows that the pharmacodynamically active form of molsidomine in humans is the metabolite SIN-1. The changes in the finger plethysmogram produced by SIN-1 suggest that in addition to the effect on the venous site, SIN-1 also dilates the peripheral arterial site.

Adult↗