Oral bioavailability and pharmacokinetics of sildenafil citrate dry foam tablets in rats

Abstract

Sildenafil has low water solubility and oral bioavailability. Dry foam formulations of solid dosage forms of poorly water-soluble drugs may exhibit improved dissolution and bioavailability. We previously developed a sildenafil citrate dry foam tablet formulation and found that it had an improved dissolution profile. In this study, we investigated the pharmacokinetic parameters of sildenafil dry foam tablets in rats after oral administration (at a dose equivalent to 20 mg/kg of sildenafil) and compared them with those of commercial sildenafil tablet and dry powder formulations. LC/MS/MS analysis of plasma sildenafil concentration revealed that the AUCs of sildenafil and N-desmethyl sildenafil in the sildenafil citrate dry foam tablet group were significantly higher (150% and 110%, respectively; P < 0.05) than those in the commercial tablet group and (190% and 120%, respectively; P < 0.05) in the sildenafil citrate powder group. The systemic bioavailability (F value) of sildenafil citrate dry foam tablet was 1.5 and 1.9 times higher than that of commercial sildenafil film-coated tablet and sildenafil powder, respectively. This indicates that the systemic bioavailability of sildenafil was increased when it was prepared as a dry foam tablet formulation.

Keywords

• sildenafil citrate
• pharmacokinetics
• bioavailability
• dry foam tablet