Contraceptives vaginal delivery

Johansson, E.D.B., and R. Sitruk-Ware. 2004. New delivery systems in contraception Vaginal rings. Am J Obstet Gynecol 190 S54. 

Zavos, P. M., and Correa, J. R. (1997), Vaginal delivery of new formulations of nonoxynol-9 coprecipitated with polyvinylpyrrolidone in rabbits. Comparisons between two formulation delivery systems, Contraception, 56,123-127. 

Landgren, B. Aedo, A. Johannisson, E. Cekan, S. Pharmacokinetic studies with a vaginal delivery system releasing levonorgestrel at a near zero order rate for one year. Contraception 1994, 49, 139-150. 

Sustained- and controlled-release devices for drug delivery in the vaginal and uterine areas are most often for the delivery of contraceptive steroid hormones. The advantages in administration by this route—prolonged release, minimal systemic side effects, and an increase in bioavailability—allow for less total drug than with an oral dose. First-pass metabolism that inactivates many steroid hormones can be avoided [183,184],... 

Solutions (lavages) and foams are liquid preparations. The foams differ from the solutions in the presence of a suitable propellant, in the formulation, and the type of container, a pressurized delivery device. Plasma concentration profiles obtained after solution administration are characterized by a burst effect followed by a rapid decrease below therapeutic levels, due to the low residence time of the formulation in the vaginal cavity. Such preparations are designed to achieve a local effect particularly in case of inflammations or infections caused by bacteria or yeasts (anaerobic bacteria or Candida species). Nonoxynol-9 (N-9) foam is used as a contraceptive and against sexually transmitted diseases [19]. 

In conclusion, contraception therapies with vaginal rings present excellent efficacy with little risk of side effects and appear to be as effective as oral contraception and IUD, in terms of pregnancy prevention [42]. Moreover, rings are characterized by important benefits like ease of use, long-term schedule, and user-controlled application. These versatile drug delivery systems appear to be safe, effective, and acceptable. 

D Cruz, O. I, and Uckun, F. M. (2001), Gel-microemulsions as vaginal spermicides and intravaginal drug delivery vehicles, Contraception, 64,113-123. 

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