Sildenafil citrate-Glycyrrhizin/Eudragit binary spray dried microparticles: A sexual behavior studies on male rats

Sildenafil citrate (VIAGRA®) is a phosphodiasterase inhibitor 5 used for the treatment of male erectile dysfunction. Low aqueous solubility of sildenafil citrate limits their bioavailability and hence therapeutic effects. The aim of the present study was to develop a sildenafil citrate-Glycyrrhizin/Eudragit binary spray dried microparticles with a view to improve its aqueous solubility and examine its effect of sexual behavior on male rats. Microparticles of sildenafil citrate were prepared in three different ratios of sildenafil citrate-Glycyrrhizin/Eudragit (1:0.5, 1:1 & 1:2) by spray drying technique and evaluated for Particle size, size distribution, entrapment efficiency, DSC, FTIR, XRD, SEM and in vitro release studies. Among the six different formulae (F1, F2, F3, F4, F5, and F6), Glycyrrhizin (F2) and Eudragit (F4) based microparticles were optimized with an average particle size of 2.56 μm, 2.94 μm and high entrapment values 73.06%, 67.52% respectively. DSC, FTIR, and XRD confirmed the amorphous state of the encapsulated Sildenafil citrate. In vitro release studies exhibited significant results. Furthermore, its sexual behavior activity in male rats was much better as compared to pure sildenafil citrate. The overall results suggest that Glycyrrhizin based microparticles could be a potential option for sildenafil citrate delivery.