Enhancing vaginal drug delivery: the nanoemulsion gel strategy

In the 21st century, 75 % of women encounter vaginal malfunctions (cervicitis, mucoid ectopy, aerobic vaginitis, candidiasis, bacterial vaginosis, degenerated vaginitis, desquamative chronic vaginitis, and sexually transmitted infections) that clinically manifest as irritation, awkwardness, irregular bleeding, or evacuation. Vaginal drug delivery, an approach to treat the aforementioned diseases, primarily focuses on vaginal epithelium thickness, cyclic changes, vaginal secretions, mucus and enzymatic activity, pH, local microflora, and the presence of efflux transporters for their fabrication. There has been a growing interest in nanoemulsion gel for drug delivery to the vagina in comparison to conventional vaginal delivery systems (rings and gels). This review provides an in-depth examination of nanoemulsion gel formulation, highlighting key considerations such as the choice of vehicles, gel-forming agents, and permeation enhancers. It further explores formulation techniques, stability issues, and novel approaches like mucoadhesive and controlled-release systems. The biocompatibility and safety of nanoemulsion gels are also critically assessed, along with regulatory aspects. The paper underscores the growing significance of these formulations in the management of various vaginal conditions, including infections, hormonal therapies, and contraceptive applications. As nanoemulsion gels continue to evolve, their role in optimizing vaginal drug delivery systems offers considerable potential for improving therapeutic outcomes and patient compliance.