Clinical pharmacology of drugs in their intravaginal administration

The paper deals with the characteristics of the intravaginal route of drug administration that is attractive from two points of view. Firstly, this is the ability to quickly deliver the drug directly into the disease focus. Secondly, the characteristics of the vaginal epithelium (a low metabolic activity against xenobiotics), the relatively favorable aqueous medium for acid-resistant molecules, good organ vascularization, and the entry of absorbed substances into the bloodstream, by passing the liver, create favorable conditions for the use of systemic drugs. Currently, there are many vaginal drug delivery systems: solutions, creams, ointments, gels, tampons, suppositories, capsules, pessaries, sponges, and modified-release vaginal devices (e.g. rings) Despite the ease of use, the vaginal route of drug administration can be associated with certain features, such as differences in the thickness of the mucous membrane in different phases of the menstrual cycle and in different periods of life, variations in the pH of vaginal secretion, the likelihood of dosage form leakage, the effect on the vaginal mucosa and local microbiocenosis, probable discomfort when using certain formulations. The paper describes the anatomical and histological features of the vagina, which affect the absorption of various substances and provides information on the pharmacokinetics of drugs, including those prescribed for the treatment of vaginal infections. Conclusion. Despite its many features, intravaginal administration is one of the most common and widely studied methods of drug delivery. When drugs are prescribed, it is necessary to take into account their pharmacokinetic differences that are observed in both different periods of female patient’s life and different phases of the menstrual cycle, and the associated possible fluctuations in the systemic concentration of drugs. The latter used to achieve an exclusively local effect should be characterized by a minimal systemic absorption and a minimal impact on local immunity and natural vaginal biocenosis.

intravaginal administration, pharmacokinetics, vaginal infections