Comparative bioavailability of two escitalopram formulations in healthy human volunteers

To assess the bioequivalence of two escitalopram formulations (Test formulation: escitalopram (10 mg tablet) manufactured by Apsen Farmacêutica S.A.) Reference formulation: escitalopram (Lexapro; 10 mg tablet) from Lundbeck Brasil Ltda) in healthy volunteers of both sexes.

The study was conducted using an open, randomized, two-period crossover design with at least a 21-day washout interval. Plasma samples were obtained over a 168 h period. Plasma escitalopram concentrations were analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS) with positive ion electrospray ionization using multiple reaction monitoring (MRM). The following pharmacokinetic parameters were obtained from the escitalopram plasma concentration vs. time curves: AUC(last), AUC(inf) and C(max).

The limit of quantification for escitalopram was 0.2 ng x ml(-1). The geometric mean with corresponding 90% confidence interval (CI) for Test/Reference percent ratios were 97.35% (90% CI = 90.28-104.96%) for C(max), 99.60% (90% CI = 92.93-106.74%) for AUC(last) and 99.92% (90% CI = 93.34-106.97%) for AUC(inf).

Since the 90% CI for AUClast, AUCinf and Cmax ratios were within the 80-125% interval proposed by the US FDA, it was concluded that escitalopram formulation manufactured by Apsen Farmacêutica S.A. is bioequivalent to the Lexapro formulation in regard to both the rate and the extent of absorption.