Bio equivalence Study of Two Tablet Formulations of Sildenafil

Abstract

This study was conducted in order to assess the bioequivalence of two tablet formulations containing 100 mg sildenafil (1-[4-ethoxy-3-(6,7-dihydro-l-,ethyl-7-oxo-3-propyl-lH-pyrazolo[4,3-d]pyrimi-din-5-yl)phenylsulphonyl]-4-methyl piperazine, CAS 139755-83-2). Twenty-eight healthy subjects were enrolled in a single-centre, randomised, single-dose, open-label, 2-way crossover study, with a minimum washout period of 7 days. Plasma samples were collected up to 18.0 h post-dosing. Sildenafil levels were determined by reverse liquid chromatography coupled with tandem mass spectrometry detection (LC-MS/MS). Pharmacokinetic parameters used for bioequivalence assessment [area under the concentration-time curve from time zero to time of last nonzero concentration (AUC_last) and maximum observed concentration (C_max) were main evaluation criteria; however, the area under the concentration-time curve from time zero to infinity (AUC_inf) was also analysed] were determined from the sildenafil concentration data using non-compartmental analysis. The 90% confidence intervals (obtained by analysis of variance, ANOVA) were 86.70–108.19 for Cmax, 86.67–99.26 for AUC_last and 87.19–99.82 for AUC_inf, within the predefined ranges. Bioequivalence between the two formulations was concluded both in terms of rate and extent of absorption.

Key words

CAS 139755-83-2 - Phosphodiesterase type 5, inhibitors - Sildenafil, bioequivalence, pharmacokinetics

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