Self-Emulsifying Formulation of Indomethacin with Improved Dissolution and Oral Absorption

The objective of the present study was to enhance the solubility, dissolution and hence anti-inflammatory activity of poorly soluble drug indomethacin (IMN) by formulating into self emulsifying systems.

Self emulsifying formulations were prepared using capmul MCM as oil, tween 80 as surfactant, transcutol P as cosurfactant. Fourier transform infrared spectroscopy and differential scanning calorimetry studies were conducted to know the interaction between drug and excipients. Pseudo ternary phase diagrams were constructed using surfactant and cosurfactant in 1:1 to 1:4 and 2:1 to 4:1 to know the efficient self emulsification region. The formulations were evaluated for their particle size, zeta potential, refractive index, viscosity and cloud point. In vitro dissolution studies were conducted in one part of pH 7.2 phosphate buffer and four parts of water. The pharmacokinetic parameters were analysed by Win Nonlin software.

The self emulsification was higher with the ratios 2:1, 3:1 and 1:2 of surfactant and co surfactant and the IMN formulations were prepared. The formulations were stable at different pH and dilutions. The globule size was in the range of 184.1 nm to 340.5 nm, as the ratio of oil, surfactant and cosurfactant mixture has varied effects on the size of globule. The negative charge on the globules of all formulations attributes their stability. The optimized formulation showed better release as compared to marketed product. The AUC of the optimised Self-Emulsifying Drug Delivery System was significantly higher than the marketed product.

Thus, from the present research, self emulsifying systems of IMN provide a useful alternative to enhance dissolution and hence anti inflammatory activity.