Bioequivalence assay between orally disintegrating and conventional tablet formulations in healthy volunteers.

The purpose of this study was to evaluate bioequivalence of two commercial 8 mg tablet formulations of ondansetrona available in the Brazilian market. In this study, a simple, rapid, sensitive and selective liquid chromatography-tandem mass spectrometry method is described for the determination of ondansetron in human plasma samples. The method was validated over a concentration range of 2.5-60 ng/ml and used in a bioequivalence trial between orally disintegrating and conventional tablet ondansetron formulations, to assess its usefulness in this kind of study. Vonau flash (Biolab Sanus Farmacêutica, Brazil, as test formulations) and Zofran (GlaxoSmithKline, Brazil, as reference formulation) were evaluated following a single 8 mg dose to 23 healthy volunteers of both genders. The dose was administered after an overnight fast according to a two-way crossover design. Bioequivalence between the products was determinated by calculating 90% confidence interval (90% CI) for the ratio of C(max), AUC(0-t) and AUC(0-infinity) values for the test and reference products, using logarithmically transformed data. The 90% confidence interval for the ratio of C(max) (87.5-103.8%), AUC(0-t) (89.3-107.2%) and AUC(0-infinity) (89.7-106.0%) values for the test and reference products is within the 80-125% interval, proposed by FDA, EMEA and ANVISA. It was concluded that two ondansetron formulations are bioequivalent in their rate and extent of absorption.