Vaginal delivery of medication is advantageous in allowing for the medication to avoid first-pass metabolism and gastrointestinal degradation. Lined with non-cornified, stratified squamous epithelium, the vaginal mucosa offers a large surface area and rich blood supply, making it a promising site for delivery of medication in the treatment of conditions such as vaginitis (inflammation), bacterial, fungal, and viral infections. The vagina has self-cleansing potential with large secretions of vaginal fluid, often limiting the residence time (time at the site of action) of conventional vaginal dosage forms such as tablets, creams, gels, and foams. For this reason, the use of mucoadhesive polymers as a delivery system is preferred. Mucoadhesive polymers can prevent leakage by prolonging the contact time between the medication and the mucosal tissue. Due to the prolonged contact with the vaginal mucosa, an ideal mucoadhesive polymer should be non-toxic and non-irritating.
The aim of this study was to evaluate the safety and toxicological profile of MucoLox, in comparison to that of Triton X-100 (positive control), using a 3-dimensional (3D) model of the human vaginal mucosa. MucoLox is a proprietary polymer gel designed to improve mucoadhesion and prolong retention of medication at application sites within the vaginal mucosa. Triton X-100, which served as a positive control in this study, is a nonionic surfactant that can be used as a solubilizer, stabilizer, and emulsifier.
The vaginal mucosa is a common site for local and systemic delivery of medication. Mucoadhesive polymers have been developed to increase residence time and prevent leakage of medication often seen with conventional vaginal delivery systems. The intimate contact between the mucoadhesive polymer and the vaginal mucosal tissue requires the delivery system to be non-irritating and non-toxic. This study aims to compare the safety and toxicological profile of MucoLox, a polymer gel, to that of Triton™ X-100, a positive control, using a 3D model of the human vaginal mucosa. Results have demonstrated that MucoLox was less toxic as it can bind to the vaginal tissue approximately 14 times longer than Triton X-100 before cell viability is reduced to 50%. Compounded medicines prepared with MucoLox are then likely to remain at the site of action for a long period of time without causing damage to the vaginal tissue, potentially reducing the need for frequent dosing and increasing the effectiveness of each dose administration.
Figure 1. Illustration of the EpiVaginal tissue model.
Figure 2. Toxicological profiles of MucoLox and Triton X-100.
MucoLox is a mucoadhesive polymer that allows the medication to adhere to the vaginal tissue for a long period of time, despite the regular secretions of vaginal fluid. The ability of mucoadhesive polymers to bind to the vaginal tissue without causing toxicity is a very important characteristic to be considered and, therefore, the safety and toxicological profile of MucoLox was evaluated. Vaginal toxicity can cause irritation and tissue damage, which weaken the natural defenses of the vaginal mucosa, increasing the risk of infections such as HIV and herpes simplex. Study results have demonstrated that MucoLox exerts minimal toxicity on the vaginal mucosa following over 20 hr of exposure.
Compounded medicines prepared with MucoLox are then likely to remain at the site of action for a long period of time without causing damage to the vaginal tissue, potentially reducing the need for frequent dosing and increasing the effectiveness of each dose administration.