Preparation and evaluation of aceclofenac topical microemulsion

A topical preparation containing aceclofenac was developed using an o/w microemulsion system. Isopropyl myristate was chosen as the oil phase as it showed a good solubilising capacity. Pseudo-ternary phase diagrams were used to obtain the concentration ranges of the oil, surfactant (Labrasol) and co-surfactant (plurol oleique) for microemulsion formation. Five different formulations were formulated with various amount of the oil (5-25%), water (10-50%), and the mixture of surfactant and co-surfactant at the ratio of 4 (45-65%). In vitro permeability of aceclofenac from the microemulsions was evaluated using Keshary Chien diffusion cells with 0.45-μm cellulose acetate membrane. The amount of the aceclofenac permeated was analyzed by HPLC and the droplet size and zeta potential of the microemulsions was determined using a Zetasizer Nano-ZS. The mean diameters of the microemulsion droplets approximately ranged between 154 - 434 nm, and the permeability of aceclofenac incorporated into the microemulsion systems was 3 folds higher than that of the marketed formulation. These results indicate that the microemulsion system studied is a promising tool for percutaneous delivery of aceclofenac.