Recent Advances in Polymer-Based Vaginal Drug Delivery Systems

Abstract

The vagina has been considered a potential drug administration route for centuries. Most of the currently marketed and investigated vaginal formulations are composed with the use of natural or synthetic polymers having different functions in the product. The vaginal route is usually investigated as an administration site for topically acting active ingredients; however, the anatomical and physiological features of the vagina make it suitable also for drug systemic absorption. In this review, the most important natural and synthetic polymers used in vaginal products are summarized and described, with special attention paid to the properties important in terms of vaginal application. Moreover, the current knowledge on the commonly applied and innovative dosage forms designed for vaginal administration was presented. The aim of this work was to highlight the most recent research directions and indicate challenges related to vaginal drug administrations. As revealed in the literature overview, intravaginal products still gain enormous scientific attention, and novel polymers and formulations are still explored. However, there are research areas that require more extensive studies in order to provide the safety of novel vaginal products.

The Expanded Role of Chitosan in Localized Antimicrobial Therapy

“…Due to the self-cleansing action of the vaginal tract, locally administered formulations often fail to persist at the site of action long enough to assure sufficient therapeutic effect [281]. Vaginal pH, the thickness of the epithelium, and the production of vaginal fluid and mucus all vary, depending on the phase of the menstrual cycle, sexual activity, age, and the presence of concomitant diseases [282].…”

“…Semisolid formulations in the form of vaginal gels are one of the most extensively investigated vaginal dosage forms [282]. In particular, polymer-based hydrogels are known as a promising strategy to achieve improved localized therapy of vaginal infections [262].…”

“…Vaginal films are considered solid dosage forms and are usually thin, soft, and flexible and disperse or dissolve in contact with vaginal fluids. Films are formulated using polymers, either one or a combination of polymers, and due to its mucoadhesive and antimicrobial properties, chitosan is highly suitable for vaginal film preparation [282]. Mishra et al prepared a mucoadhesive vaginal film containing fluconazole by using polymers chitosan and pectin with glycerol as plasticizer [322].…”

Application of Sol–Gels for Treatment of Gynaecological Conditions—Physiological Perspectives and Emerging Concepts in Intravaginal Drug Delivery

“…Some of the earliest reports of administering medications directly to the vaginal cavity date back to 1850 BC, used primarily for contraception and treatment of vaginal inflammation. However, its clinical use was approved only in the late 1970s and significant advances have been made in the past five decades, particularly in the development of vaginal microbicides for HIV prophylaxis [ 19 , 50 ]. Given the advances in pharmaceutical technologies over the last two decades, preference has firmly moved towards the vaginal route of drug delivery for diseases/ailments of the FRT [ 18 ].…”

“…A variety of active pharmaceutical ingredients (APIs), including antibacterials, antifungals, antiprotozoals, anti-virals, labour inducers, spermicidal agents, and sexual hormones, have been formulated in vaginal dosage forms [ 4 , 20 , 51 ]. Nevertheless, vaginal use is restricted by cultural sensitivity, patient compliance, and the highly variable anatomical and physiological features of FRT over a lifetime, which needs to be borne in mind when designing products for vaginal delivery [ 50 ]. Moreover, the effect of a vaginal formulation on the adjacent healthy tissue should also be taken into account, since any damage could disrupt the vaginal microbiome balance and increase susceptibility to infection [ 19 ].…”