Michael Retsky
The bioavailability and bioequivalence of two different film coated tablets containing ethinylestradiol and gestodene were investigated in 36 healthy female volunteers after oral single-dose administration. The study was performed according to a single-center, randomized, single-dose, 2-way cross-over design with a wash-out phase of 28 days. Blood samples for pharmacokinetic profiling were taken postdose up to 72 h (ethinylestradiol) and 96 h (gestodene). Ethinylestradiol and gestodene plasma concentrations were determined with a validated LC-MS/MS method. Bioequivalence between the products was determined by calculating 90% confidence intervals (90% I.C) for the ratio of AUC0-t and Cmax values for the test and reference products, using logarithmic transformed data. The 90% confidence intervals of ethinylestradiol were 98.49% - 109.19%, and 100.62% - 111.69%, respectively. The 90% confidence intervals of gestodene were 94.07% - 105.91%, and 110.19% - 124.73%, respectively. Since the 90% confidence intervals for Cmax and AUC0-t were within the 80 - 125% interval proposed by Food and Drug Administration, it was concluded that the two ethinylestradiol and gestodene formulations are bioequivalent in their rate and extent of absorption.