Comparative pharmacokinetics of two tablet formulations of amoxicillin: Bioequivalence assessment

The aim of the present study was to compare the bioavailability of amoxicillin (CAS 26787-78-0) from two different amoxicillin tablets (Demoksil (R) 1 g tablet as test preparation and 1 g tablet of the originator product as reference preparation). The study was conducted according to an open-label, randomised two-period cross-over design with a wash-out phase of 4-7 days. Blood samples for pharmacokinetic profiling were taken up to 10 h post-dose, and amoxicillin plasma concentrations were determined with a validated LC-MS/MS method. Maximum plasma concentrations (C-max) of 13,296.4 ng/ml (test) and 12,797.7 ng/ml (reference) were achieved. Areas under the plasma concentration-time curve (AUC(0-infinity)) of 39,556.7 ng . h/ml (test) and 38,599.1 ng . h/ml (reference) were calculated. The median t(max) was 1.62 h (test) and 1.54 h (reference). Plasma elimination half-lives (t(1/2)) of 1.64 h (test) and 1.65 h (reference) were determined. Both primary target parameters, AUC(0-infinity) and C-max were tested parametrically by analysis of variance (ANOVA) and the 90% confidence intervals were between 96.76%-108.46% (AUC(0-infinity)) and 97.80%-111.98% (C-max). Bioequivalence between test and reference preparation was demonstrated since for both parameters, AUC and C-max the 90% confidence intervals of the T/R-ratios of logarithmically transformed data were in the generally accepted range of 80%-125%.