Novel Emulsion Base for Vaginal Yeast Infection with Half Drug Concentration

The dissolution of the drug in the vaginal cavity strongly influences the efficacy of the product due to insufficient moisture at the vaginal site. This study was undertaken to develop semi-solid dosage forms of miconazole nitrate to optimize its release. Formulations containing miconazole nitrate at 2% were developed using hypromellose gel, non-ionic emulsion, and cationic emulsion. The effect of penetration enhancers such as propylene glycol, dimethyl sulfoxide (DMSO), and diethylene glycol monoethyl ether at various concentrations was studied. Diffusion studies were carried out to evaluate the drug release and compared it against a commercial product. Formulation with the highest drug release was further evaluated at half (1%) drug concentration. Formulation with reduced drug levels along with the commercial product was evaluated for drug release for an extended time using human cadaver skin. The general order of average cumulative drug release from three bases was observed to be cationic emulsion > hydroxypropyl methylcellulose >non-ionic emulsion. Among all samples, the cationic emulsion with 5% DMSO gave a maximum drug release of 7.27 ± 0.2 mg/cm2 with a flux of 0.70 mg/cm2/min compared to only 3.09 ± 0.1 mg/cm2 drug release with 0.51 mg/cm2/min flux for brand product. The average cumulative drug release for formulation with half (1%) drug and brand (2% drug) over a period of 12 h through human cadaver skin was observed to be 8.28 ± 0.9 mg/cm2 and 8.71 ± 0.9 mg/cm2, respectively. This observation was in conformance with the in vitro antifungal studies showing an equivalent zone of inhibition. Keywords: Cationic emulsion, Drug release, Dimethylsulfoxide, In vitro antifungal study