Improvement of dissolution of a class II poorly water-soluble drug, by developing a five-component self-nanoemulsifying drug delivery system

Abstract

Purpose of this study is to develop a self-nano emulsifying drug delivery system (SNEDDS) to improve the dissolution of tadalafil and to overcome two formulation challenges namely, increasing the tadalafil solubility in the preconcentrate using a cosolvent, as well as guarding against the drug precipitation upon dilution by adding a precipitation inhibitor (PI). The formulation steps included the choice of oil through examining the saturated solubility of tadalafil in the different oils. Then, a factorial design studying different surfactants/cosurfactants mixtures was done to determine the required hydrophilic-lipophilic balance (HLB), as well as the chemical nature suitable to the oil of choice (Capryol™ 90). A ternary phase diagram was constructed to identify the region of SNEDDS. The ability of various cosolvents to increase the tadalafil saturated solubility in the preconcentrate was investigated. Then, a factorial design was adopted to investigate the different PI types and concentrations. An in-vitro dissolution study was done to compare the percent drug dissolved from the SNEDDS, Cialis®, and the plain drug. Conclusion: 10% Capryol™ 90, Tween®80 and Transcutol®HP Smix 7:2 (HLB 12) were used to prepare the SNEDDS. PEG 400 and 3%HPMC were added. 80% of the drug was dissolved from the SNEDDS in 5 min.