Vagina, a promising route for drug delivery

Vaginal drug delivery is a promising avenue for local and systemic therapy. Compared to other delivery systems, vaginal delivery has the advantages of large specific surface area, abundant blood supply, and avoidance of the hepatic first-pass effect. This article reviews the present status of intravaginal drug delivery system in terms of solid and semisolid formulations. The anatomy, histology, and microenvironment of the vagina are described, and the first intrauterine effect and the mechanism of drug diffusion and absorption are briefly discussed. In addition, some limitations of the vaginal administration, such as the effect of self-cleaning and the gravity that may lead to poor absorption and retention, are discussed. To address these challenges, bioadhesive polymers and nanosystems have been employed to vaginal delivery. We also discuss the acceptability of vaginal products, which can affect the application even the efficacy of the preparations.