Comparative pharmacodynamics of azithromycin and roxithromycin with S. pyogenes and S. pneumoniae in a model that simulates in vitro pharmacokinetics in human tonsils.

Most macrolides penetrate and persist in peripheral tissues, irrespective of plasma concentrations. For this reason, comparative pharmacodynamics of macrolides might be better based on tissue rather than plasma pharmacokinetics. The present study compares the antimicrobial effects of azithromycin and roxithromycin on Streptococcus pyogenes and Streptococcus pneumoniae using in vitro simulations of steady-state pharmacokinetics in human tonsils expected after a third 500 mg dose of azithromycin administered once a day and after a sixth 150 mg dose of roxithromycin administered twice a day.

[Determination of bifonazole using HPLC in pharmacokinetic studies].

A sensitive method for HPLC quantification of bifonazole, an antimycotic drug, in the skin and plasma was developed. The skin samples were homogenized with the use of a physiological solution (1:5) and then centrifuged at 2000 r.p.

[Correlation between pharmacokinetic parameters of rifampicin and its biologically active metabolite as related to estimation of the relative bioavailability of the antibiotic].

In the bioavailability studies with drugs biotransformed to biologically active metabolities only the concentrations of the parent drug (PD) are usually taken into account even when the pharmacokinetic data on the metabolite(s) (M) are available. However, such data may be useful as an alternative source for the bioavailability determination. Moreover, the clinical outcomes often depend on both the PD and M concentrations.