Meloxicam emulgels for topical management of rheumatism: Formulation development, in vitro and in vivo characterization.

PURPOSE: The study designed, formulated and evaluated meloxicam emulgels as a potential alternative topical treatment option for rheumatism. METHODS: A 3(2) factorial design was employed to formulate nine preliminary meloxicam emulgels (Formulations F1 - F9). The influences of carbopol-934 and menthol as gelling agent and drug release enhancer, respectively, were correlated with four pharmaceutical properties of the formulated emulgels namely viscosity, spreadability, and cumulative drug release at one hour and at eight hours. Using the generated data and applying the Design Expert® modelling software, two optimized meloxicam emulgels (Formulations F10 and F11) were designed, formulated and evaluated. In vivo anti-inflammatory efficacy was conducted using carrageenan-induced rat paw oedema method. Drug release kinetics was modelled using DDSolver® dissolution software. RESULTS: All formulations were homogenous with no observable grittiness or phase separation. The optimized Formulations F10 and F11 had pH 6.5 and 6.4, viscosity of 23656 and 24524 mPa.s, spreadability of 9.9 and 9.5 cm, and drug content of 90.4% and 92.9%, respectively, all within optimal values. The cumulative percentage of drug released was 21.0% and 22.9% after one hour and 50.1% and 55.8% after eight hours for Formulations F10 and F11, respectively. Drug release kinetics exhibited Fickian diffusion best described by Korsmeyer-Peppas model. Paw volume inhibition by Formulation F11 at two and three hours after carrageenan injection was statistically significant (p < 0.05). CONCLUSION: The optimized meloxicam emulgels had high pharmaceutical quality and were pharmacologically active. Further optimization could potentially provide a safe and efficacious alternative treatment option for rheumatism.