Development of metronidazole microsponge incorporated into carbomer-based vaginal gel

Bacterial vaginosis (BV) is a vaginal infection caused by excessive bacterial growth, thus disrupting the natural balance of bacteria inside the vagina. Metronidazole becomes a drug of choice and a widely prescribed drug for the treatment of BV. However, when applied topically, metronidazole has a low vaginal residence time because of the natural washing mechanism of the vagina. This study aimed to improve the retention time of metronidazole inside the vagina and control its release profile. This study was prepared 4 formulas of gel for metronidazole microsponges with some concentration ratio of carbomer and triethanolamine. The evaluations carried out to test the efficacy of the developed formulation included organoleptic, pH measurement, spreadability, viscosity, mucoadhesive properties, permeation test using Franz diffusion cell and retention test. The results showed that the gel appearance was white, odourless and homogenous. The characteristics of all prepared gel for pH, viscosity, spreadability, and mucoadhesive ability were appropriate to the required standard for vaginal delivery. The permeation and retention test showed that F3 with the carbomer and triethanolamine concentration of 1.25%: 1.75% was able to retain and controlled the drug release locally in the vaginal mucosa. This study provides an alternative strategy in drug formulation for the treatment of BV.