Preparation and in vitro evaluation of self-nanoemulsifying drug delivery systems (SNEDDS) containing clotrimazole

This study sought to formulate and evaluate a self-nanoemulsified drug delivery system (SNEDDS) for clotrimazole (CT), a poorly water-soluble antimycotic drug, used in vaginal delivery. SNEDDS was developed to increase the CT dissolution rate, solubility, and ultimately bioavailability. The solubility of CT in various oils, surfactants, and co-surfactants was determined. Based on solubility studies, oil phase (oleic acid without or with coconut oil), surfactant (Tween 20), and co-surfactants (PEG 200 and n-butanol) were selected and grouped in two combinations for phase studies. Pseudo-ternary phase diagrams were used to evaluate the area of self-nanoemulsification. Essential properties of the prepared systems with regard to emulsion droplet size and turbidity value were determined. In order to investigate the potential for interaction between any of the SNEDDS ingredients used, FTIR spectroscopy was performed. In vitro release studies were performed with SNEDDS formulations in capsules, and the plain drug served as a control. The droplet size of the nanoemulsion was greatly affected by the ratio of the surfactant and co-surfactant. Based on the results with regard to droplet size, turbidity values, and complete drug release after 3 h, three optimized formulations were selected; each contained oleic acid/coconut oil/Tween 20/PEG 200/n-butanol in ratios of 10:0:60:15:15 (%, w/w), 7.5:2.5:53.5:13.3:13.3 (%, w/w), and 6.7:3.3:60:10:10 (%, w/w), respectively. Results suggested that the prepared SNEDDS formulations produced acceptable properties in terms of immediate drug release and could increase the bioavailability of CT.