Experimental measurement and thermodynamic modeling of sildenafil citrate drug solubility in supercritical carbon dioxide

Abstract

According to the sexual dysfunction definitions [1], erectile dysfunction is the persistent inability to get and maintain an erection for satisfactory sexual performance. Among available methods for treatment, oral medications are the most common. In this regard, sildenafil citrate belongs to a class of medications called phosphodiesterase type 5 (PDE 5) inhibitors, which can restore the natural process of erection. Despite rapid absorption after administration, absolute bioavailability of sildenafil citrate has been reported about 40% [2]. One of solutions to improve the bioavailability of this medicine is production of nanoparticles via supercritical fluid (SCF) based technologies [3]. To follow these technologies, knowledge of solubility of sildenafil citrate in SCF at different temperatures and pressures, is the first step. However, experimental performances at various operating conditions are usually impractical. Therefore, application of an acceptable theoretical approach such as semi-empirical models [4] would be found beneficial.