Journal of Bioequivalence & Bioavailability

Abstract

Relative Bioavailability of Chewable and Conventional Film-Coated Tablet Formulations of Sildenafil 100 mg in Healthy Volunteers Under Fasting Conditions

Fermin Valenzuela, Gabriela Davila, Yamanqui Ibañez, Luis Garcia, Penelope Crownover, Regina Gómez-Palacio, Juan Ovalle, Cesar Velasco and Bimal Malhotra

Pharmacokinetics and bioavailability of a chewable tablet formulation of sildenafil citrate 100 mg developed using taste-masking technology and taken with or without water (chewed until full disintegration and then swallowed) versus the conventional film-coated sildenafil tablet (Viagra ® ) taken with water were evaluated in the fasted state in a randomized, open-label, single-dose, 3-period crossover study in 30 healthy men aged 18 to 40 years (mean ± SD, 24±4 y). Sildenafil plasma concentrations were determined using a validated high-performance liquid chromatography method with ultraviolet detection. Bioequivalence criteria were 90% classic and Westlake CIs within 80% to 125% for test/reference ratios; limit tests applied were Schuirmann unilateral double t test and the Anderson-Hauck test. For area under the curve (AUC), bioequivalence criteria were met for all the treatments studied. For maximum plasma concentration (C max ), bioequivalence criteria were met for the chewable tablet with water relative to Viagra when using the Westlake CI. The chewable tablet without water had equivalent AUC, but the C max was up to 22% lower when compared with Viagra or with the chewable tablet with water. Median time to C max was lowest for the chewable tablet with water (0.75 h) versus Viagra (1.0 h) or the chewable tablet without water (1.75 h). Adverse events with the chewable tablet were consistent with the tolerability profile of Viagra. Only 1 (3%, chewable tablet with water) and 4 (13%, chewable tablet without water) subjects reported bitter taste, demonstrating successful taste masking.