Formulation Studies of Solid Self-Emulsifying Drug Delivery System of Ivermectin

Abstract Background: The suggested dose of ivermectin is 300 μG/kg/day for onchocerciasis but it has low water solubility and poor oral bioavailability. Aim: To prepare and evaluate a solid lipid-based self-emulsifying drug delivery system of ivermectin. Materials and methods: Based on supersaturated solubility study, oil, surfactant, and co-surfactant were selected. On the basis of ternary phase diagrams and simplex-lattice design, self-emulsifying, drug delivery formulations had been developed and optimized. Ivermectin-excipients compatibility studies were performed using differential scanning calorimetry and Fourier transform infrared spectroscopy. Solid self-emulsifying drug delivery formulation was formulated from the optimized batch by surface assimilation method and filled into hard gelatin capsules. In vitro release rate and in vivo pharmacokinetic parameters of ivermectin from the capsules were determined. Two-tailed paired t-test/Dunnett multiple comparison tests were performed for in vivo pharmacokinetic parameter at 95 % of confidence level. Results: Soybeans oil, tween 80, and span 80 were selected as oil, surfactant, and co-surfactant respectively. The ternary diagrams were shown the maximum area for emulsion in 1:2 surfactant/co-surfactant ratio. The optimized batch had found with 30 mg ivermectin, 6.17 g soybeans oil, 0.30 g tween 80, and 3.50 g span 80. All differential scanning calorimetry and Fourier transform infrared characteristic peaks of the optimized formulation were identical with that of pure ivermectin. The area under the curve of ivermectin from the capsule was about two-fold higher than that of ivermectin suspension. Conclusions: Solid self-emulsifying drug delivery system was an effective oral solid dosage form to improve the oral bioavailability of ivermectin.