Comprehensive Evaluation of a Mucoadhesive Self-Emulsifying Anhydrous Base for Vaginal Drug Delivery

Background/Objectives: Compounded vaginal creams are widely used for conditions such as hormone replacement therapy, vaginal dryness, low libido, vaginal infections, etc. Recent research highlights the potential of using anhydrous bases to extend shelf life, particularly when combined with self-emulsifying and mucoadhesive properties that improve mucosal retention and enhance drug bioavailability. This study provides in vitro and ex vivo evaluation of an anhydrous vaginal base. Methods: Key quality indicators such as irritation potential, leakage potential, pH compatibility, mucoadhesion, and self-emulsification were assessed using the chorioallantoic membrane Hen's Egg Test, MTT assay, texture analysis, and fluorescence microscopy. Results: The anhydrous vaginal base demonstrated high cell viability (>78%) and non-irritant potential (IS = 2.5) in in vitro assays. It maintained physiological vaginal pH (4.56 ± 0.05), showed strong mucoadhesive properties comparable to commercial products, and exhibited minimal leakage. Ex vivo studies confirmed its prolonged retention on vaginal tissues. The anhydrous vaginal base formed stable emulsions upon contact with vaginal fluid simulant, effectively distributing both lipophilic and hydrophilic compounds. Conclusions: Compared to water-containing bases, an anhydrous vaginal base shows advantages: longer retention time and lower leakage; adaptability to varying vaginal fluid levels; and efficient dispersion of both hydrophilic and lipophilic active pharmaceutical ingredients. These features support its potential use in compounded vaginal products, minimizing stability risks and enhancing patient compliance and therapeutic outcomes.