Nanomedicine for vaginal drug delivery

Vaginal route for drug administration can be exploited for the management of many genital conditions such as microbial infections, cancer, and vaginitis. This route offers various advantages, that is, avoidance of hepatic first-pass effect, ease of application, and the possibility of both local and systemic drug delivery. However, the challenge comes from the continuous changes in the vaginal environment related to its mucus, pH, enzyme activity, microflora, and menstrual cycle. Nanoscale drug delivery systems can reduce the influence of physiological factors on drug efficacy, prolong drug release and reduce dose frequency, minimize adverse effects associated with conventional dosage forms, and enhance patient compliance. Nanoparticle engineering necessitates an in-depth comprehension of their mucus penetration and retention behavior in vaginal mucosa as a function of their size and surface characteristics, and formulation. The most common nanosystems investigated for vaginal administration are reviewed, giving special attention to the recent advances in their development.