vaginal delivery

Vaginal delivery means placing a drug into the vagina to act either locally on vaginal and surrounding tissues or to be absorbed into the bloodstream for a body-wide effect. Most familiar uses are local — treating infections or dryness — but the same well-supplied lining can also serve as a systemic absorption surface.

The vaginal mucosa is moist, richly vascularized, and fairly permeable, and like the lower rectum its blood largely bypasses the liver, so absorbed drug can avoid much first-pass metabolism. This makes it attractive for hormones (estrogens, progesterone) and for steady, prolonged release. Dosage forms include pessaries (vaginal suppositories), tablets, creams, gels, foams, and vaginal rings — flexible polymer rings worn for weeks that release hormone continuously.

A distinctive challenge is that the vaginal environment is not constant: its pH (normally acidic), the thickness of the lining, secretions, and permeability all shift with the menstrual cycle, age, and menopausal status, so absorption can vary considerably. Retention can be imperfect (leakage), and acceptability and convenience matter for adherence. Formulations often use mucoadhesive or in-situ gelling systems to improve contact time and reduce messiness.