FORMULATION AND EVALUATION OF SELF EMULSIFYING DRUG DELIVERY SYSTEM OF POORLY SOLUBLE ANALGESIC

In the present work, the aim was to prepare a self-emulsifying drug delivery system of poorly soluble analgesic, mefenamic acid to improve its solubility with a view to enhance its oral bioavailability. From the solubility studies the selected oil, surfactant and co-surfactant was soyabean oil; tween 80, span 20; glycerol. Blends of surfactant mixtures containing tween 80, span 20, and glycerol were prepared. Three ratios of S-mix containing tween 80: span 20: glycerol viz. 1:0.25:1, 1:1:1, 2:2:1; were used to construct pseudo ternary phase diagram to select nine formulation composition. Nine self-emulsifying formulations of mefenamic were prepared and evaluated for optical transparency, low refractive index, uniformity index, low viscosity, and drug release. The best formulations in all aspects of the evaluation were subjected to stability testing. The optimized formulation has been found to have good physical stability and longest shelf life of 13.45 months under accelerated storage conditions with degradation rate constant 1.38 x 10(-3) months.