Bioequivalence of two amoxicillin-potassium clavulanate oral preparations in dogs

Abstract

The aim of this trial was to carry out a bioequivalence (BE) study in dogs using a generic preparation of amoxicillin-potassium clavulanate vs a commercially available reference preparation, both claiming to achieve  plasma concentrations that allow a 12 h dosing interval after oral administration. The oral pharmacokinetic profiles of a single dose of each preparation were carried out in 12 adult mongrel dogs in a crossover model with a 10 day washout period at a dose of 12.5 mg/kg of trihydrate amoxicillin and potassium clavulanate as tablets. A composite determination of amoxicillin-potassium clavulanate concentration in each sample of plasma was carried out in triplicate, using a microbiological agar diffusion analysis. Pharmacokinetic analysis was carried out with a non-compartmental model. Statistical analysis of pharmacokinetic variables was carried out by ANOVA and Bonferroni t test, setting a P < 0.05. In accordance with international standards, it was found that the generic preparation failed to be bioequivalent, i.e: AUC0-∞ 9.08 ± 0.26 μg h/ml and Cmax 5.48 ± 0.19 μg/ml for the generic preparation vs AUC0-∞ 13.28 ± 0. 30 μg h/ml and Cmax 2.9 ± 0.17 μg/ml for the reference one. A 0.25 μg/ml breakpoint can be set as minimum effective plasma concentration for amoxicillin; hence the generic preparation requires a dose interval of eight h.