Vaginal drug delivery developments

Human vagina is an S-shaped fibromuscular collapsible tube, 6-10 cm long, extending from cervix to uterus and located between the bladder and the rectum [1], It presents unique features in terms of secretions (pH and composition) and microflora, which must be considered during the development and the evaluation of vaginal drug delivery systems [2],... 

Yotsuyanagi, T., et al. 1975. Systems approaches to vaginal drug delivery of drugs. Development of in situ vaginal drug absorption procedure. J Pharm Sci 64 71. 

Recent advances in gel and polymer technology boosted research, opening new possibilities for vaginal drug delivery [97], Indeed, the development of new and... 

Richardson, J.L., and T.I. Armstrong. 1999. Vaginal delivery of calcitonin by hyaluronic acid formulations. In Bioadhesive drug delivery systems Fundamentals, novel approaches, and development, eds. E. Mathiowitz, D.E. Chickering, III, and C.M. Lehr. Basel Marcel Dekker. 

Evaluation of pharmaceutical systems is consensually recognized as an important component of their development and quality control. Although evaluation of general features (e.g., drug content) is also required for vaginal formulations, this section focuses only upon some of the most important parameters that are intimately related to drug delivery systems specifically designed to be administered by this route. 

The cyclic variation in vaginal drug permeability observed in rhesus monkeys in association with the rhythmic pattern of the sexual cycle suggests that the vaginal absorption data generated in the rhesus monkeys may be more reflective of what will occur in humans. The rhesus monkey is, therefore, a good animal model for the research and development of intravaginal delivery devices. 

Rossi, S., Marciello, M., Ferrari, F., et al., 2012. Development of sponge-like dressings for mucosal/transmucosal drug delivery into vaginal cavity. Pharm. Dev. Technol. 17, 219-226. 

Conventional systems do not offer sufficient flexibility in controlling drug-release rate and sustaining the release over time periods extending from days to months. Therefore specific modified release vaginal delivery systems are continuously under development and are based on mucoadhesive systems. Penetration enhancement may represent a necessary feature for certain delivery systems, particularly when the absorption regards a macromolecule (such as a peptide or a protein). 

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