Comparative In vitro Bioequivalence Evaluation of Different Brands of Amoxicillin Capsules Marketed in Tigray, Ethiopia

Abstract

The availability of multisource generic brands of amoxicillin in the market today places health professionals and patients in a difficult situation about the choice of a suitable product among numerous generic brands. The purpose of this study was to estimate the bioequivalence of amoxicillin capsules marketed in Ethiopia using in vitro tests in order to determine their interchangeability. The in vitro dissolution study was carried out on the six brands of amoxicillin capsules according to USP guidelines. To compare the dissolution profiles, a difference factor (f1), similarity factor (f2), dissolution efficiency (DE) and statistical methods were employed. Results have shown significant differences in the dissolution profiles of the brands based on the statistical analysis (p<0.0001). Pair-wise comparisons using Dunnett’s test indicated that the innovator brand has a significantly faster dissolution than the generic brands, except brand D. According to f1, f2 and DE calculations, only brand D was found to have similar dissolution profile with the innovator. Based on the in vitro studies, only brand D may be considered bioequivalent and interchangeable, while the other brands may not be considered bioequivalent and interchangeable with the innovator brand. This research highlights among other things the need for constant monitoring and surveillance on the marketed drugs by regulatory bodies to ascertain bioequivalence and quality medicines, especially for drugs like amoxicillin for which there exists evidence of non-bioequivalence from different firms, resulting in efficacy issues.