Development and Characterization of Spray-dried Amorphous Solid Dispersion of Sildenafil: In vivo Evaluation

Background and Objective: Erectile Dysfunction (ED) is a non-satisfactory age-related sexual condition caused due to physiological and psychological illness. Phosphodiesterase-5 inhibitor (PDE5I) sildenafil used for the treatment of ED, has and poor aqueous solubility and low bioavailability. Therefore, the objective of this study was to develop spray-dried amorphous solid dispersion of sildenafil using novel drug carriers; Glycyrrhizin and soluplus. Materials and Methods: Spray-drying technology was employed for the preparation of Spray Dried Amorphous Solid Dispersion (SDASD) of sildenafil by varying drug-polymer ratios. Prepared solid dispersions were characterized for yield, drug entrapment, particle size, Polydispersity Index (PDI) and zeta potential. Drug-polymer interaction was studied by Fourier-Transform Infrared Spectroscopy (FTIR), X-ray Powder Diffraction (XRD) and scanning electron microscope (SEM) examination alongside of drug release studies were done followed by in vivo evaluation of the optimized formulation in the male rats. Results: The optimized formulation SN2 showed a 90.3% yield, 40.90% drug entrapped, whereas particle size was found to be 0.710 um with 0.239 PDI and -33.7 mV zeta-potential. The cumulative drug released percentage (%) for SN2 was found to be 75.34 % in comparison with 32.93% for pure drug sildenafil. Optimized SN2 showed acceptable yield, stable dispersion system with 2.28 folds enhanced drug release. Furthermore, SN2 in vivo assessment of sexual behavior activity in male rats suggests enhanced sexual interest, libido, and erection in comparison to pure drug sildenafil and control group. Conclusion: The developed novel SDASD of Sildenafil showed increased aqueous solubility, drug release and improved therapeutic effectiveness supported by the enhanced sexual behavior of male rats as per the in vivo evaluation.