Optimized formulation for topical administration of clotrimazole using Pemulen polymeric emulsifier

Background: Emulgel topical formulation is a vehicle of potential for topical delivery of antifungal drugs. Methods: The imidazole derivative antifungal drug, clotrimazole (CZ), was formulated into emulgels using two grades of hydrophobically modified co-polymers of acrylic acid, namely Pemulen TR1 and TR2. The prepared emulgels were evaluated for their rheological properties, short- and long-term stability, in vitro release at 37 degrees C. Microbiological evaluation of the formula showed that optimum stability and release was carried out to measure its antifungal activity. Results: All formulae showed non-Newtonian shear thinning behavior with little thixotropy or antithixotropy. Five of the prepared formulae showed good physical stability under different treatment conditions. Isopropyl myristate (IPM) emulgels exhibited higher rate of CZ release than either jojoba oil (JB) or liquid paraffin-based emulgels. A selected formula containing JB together with a combination of Pemulen TR1 and TR2 showed excellent stability as well as high rate of CZ release. Microbiological evaluation of the selected formula containing similar amount of CZ revealed 1.2-folds increase in the antifungal activity compared to commercially available formulation. Conclusion: Emulgel dosage form based on Pemulen polymeric emulsifier and JB is a promising vehicle for topical delivery of CZ and further in vivo animal studies are recommended.