Development and Evaluation of an Ocular Anti-inflammatory Microemulsion

The main objective of this study is to formulate Bromfenac Microemulsion with prolonged duration of action which will help in increasing its topical bioavailability. Bromfenac belongs to the category of NSAID. A calibration curve of Bromfenac was taken in USP Phosphate buffer pH 7.4 at 268nm. Oleic acid, Poloxamer 188 and Propylene glycol were found to have maximum absorbance during solubility studies. Titration method was used to construct Pseudoternary phase diagram varying the ratio of Poloxamer 188 and Propylene glycol such as 1:1, 1:2, 1:3 and 2:1, diluting it appropriately with water. Oleic acid was then added drop-wise till turbidity was observed. Microemulsion was characterized for particle size, Osmolality, drug content and Viscosity. In-Vitro diffusion study was carried out on Keshary-chien membrane permeation cell to evaluate release pattern. Freeze thaw cycling and centrifugation were carried out to check stability of formulation. It was found from in-vitro diffusion studies of formulation that microemulsion of Bromfenac exhibited better penetration than marketed formulation. Particle size of formulation at optimized composition was found to be <100 nm (Malwern-zeta sizer). A stable formulation requiring less frequency of administration could be prepared. The rate of penetration was found to be faster than the marketed formulation.