Vaginal Formulations for Prevention of Sexual Transmission of HIV

Abstract

According to UNAIDS, as there is still no effective vaccine against HIV, pre-exposure prophylasis (PrEP) is necessary to reduce its incidence. Sexual transmission rate is higher from men to women in developing countries and vertical transmission may also occur from mother to child. Hence, vaginal formulations are an interesting proposal for the protection of women, preventing the virus from infecting vagina through different mechanisms. Several drugs, such as Dapivirine, Tenofovir or Maraviroc, have been assessed and showed to be effective in this field. These microbicides are included in different dosage forms able to release the drug once in contact with the vaginal medium. Innovative excipients are being employed for the development of different systems trying to get an easier posology through control release and high comfortability, thus leading to a better compliance. In this line, several formulations have been developed and tested, such as rings, tablets, gels or films. Some of them are nowadays in clinical trials, such as a Tenofovir gel or a Dapivirine vaginal ring. The aim of this chapter is to synthetize the research and findings in the field of the development and assessment of vaginal formulations in the PrEP of HIV sexual transmission.

Development of Dispersible Vaginal Tablets of Tenofovir Loaded Mucoadhesive Chitosan Microparticles for Anti-HIV Pre-Exposure Prophylaxis

“…Drug release from chitosan microparticles (CM) is governed by polymer swelling, drug absorption, drug diffusion, polymer erosion or degradation, and a combination of erosion and degradation. 14,22,30 The focus of the current project is to develop novel preexposure prophylactic dispersible tablets of TDF-loaded bioadhesive chitosan microparticles (DT-TCM) for intravaginal administration in view of overcoming the limitations of conventional dosage forms. The novelty of the project lies in the fact that the dispersible tablets would readily disperse into the constituent bioadhesive microparticles that adhere well to the vaginal mucosa for a considerable time period.…”

“…This interaction is crucial to the success of the formulation. Gelation of these polymers upon contact with aqueous media can be beneficial in controlling drug release via diffusion through the gel layer. ,,, Dispersible tablets composed of multiparticulate systems are advantageous over single-unit vaginal dosage forms as they are known to exhibit a more reliable vaginal mucosal retention time (Figure ). The chances of failure of such a specialized dosage form are very merger.…”

Development and evaluation of mucoadhesive bigel containing tenofovir and maraviroc for HIV prophylaxis

“…Pre-exposure prophylaxis through utilization of effective antiretroviral medications has been shown to be effective. Also, the use of highly effective antiretroviral therapies in topical formulations such as antiviral impregnated vaginal rings, tablets, biofilms, and antimicrobial gels has been extensively evaluated [4]. Compounds such as dapivirine, tenofovir, and maraviroc have been evaluated as topical antimicrobial agents in the prevention of HIV infection through sexual exposure, with varying results on efficacy shown among these compounds as topical formulations [4][5][6].…”

“…Also, the use of highly effective antiretroviral therapies in topical formulations such as antiviral impregnated vaginal rings, tablets, biofilms, and antimicrobial gels has been extensively evaluated [4]. Compounds such as dapivirine, tenofovir, and maraviroc have been evaluated as topical antimicrobial agents in the prevention of HIV infection through sexual exposure, with varying results on efficacy shown among these compounds as topical formulations [4][5][6]. This might not be unconnected to the class of the antiretrovirals and their mechanism of action, formulation strength and type, and mode and frequency of use, among other factors that might affect the efficacy in both in vitro and in vivo evaluations of these agents [7].…”

Amino Functionalized Micro-Mesoporous Hybrid Particles for the Sustained Release of the Antiretroviral Drug Tenofovir

“…These hybrid particles are intended to take part of a mucoadhesive vaginal composite, as described by Veiga-Ochoa et al [21][22][23][24][25][26]. After selecting the appropriate carrier, it must be included into the vaginal formulation for in-vivo tests, processability and comfortability assays.…”