Development and verification of mechanistic vaginal absorption and metabolism model to predict systemic exposure after vaginal ring and gel application.

AIMS: The current work describes the development of mechanistic vaginal absorption and metabolism model within Simcyp Simulator to predict systemic concentrations following vaginal application of ring and gel formulations. METHODS: Vaginal and cervix physiology parameters were incorporated in the model development. The study highlights the model assumptions including simulation results comparing systemic concentrations of 5 different compounds, namely, dapivirine, tenofovir, lidocaine, ethinylestradiol and etonogestrel, administered as vaginal ring or gel. Due to lack of data, the vaginal absorption parameters were calculated based on assumptions or optimized. The model uses release rate/in vitro release profiles with formulation characteristics to predict drug mass transfer across vaginal tissue into the systemic circulation. RESULTS: For lidocaine and tenofovir vaginal gel, the predicted to observed AUC0-t and Cmax ratios were well within 2-fold error limits. The average fold error (AFE) and absolute AFE indicating bias and precision of predictions range from 0.62 to 1.61. For dapivirine, the pharmacokinetic parameters are under and overpredicted in some studies due to lack of formulation composition details and relevance of release rate used in ring model. The predicted to observed AUC0-t and Cmax ratios were well within 2-fold error limits for etonogestrel and ethinylestradiol vaginal ring (AFEs and absolute AFEs from 0.84 to 1.83). CONCLUSION: The current study provides first of its kind physiologically based pharmacokinetic framework integrating physiology, population and formulation data to carry out in silico mechanistic vaginal absorption studies, with the potential for virtual bioequivalence assessment in the future.

Vegetable moisturizing raw material from "Caatinga" Brazilian biome: safety and efficacy evaluations of O/W cosmetic emulsions containing Kalanchoe brasiliensis extract

The purpose of this study was to evaluate the safety of Kalanchoe brasiliensis extract, followed by the development of an oil in water emulsion containing the K. brasiliensis leaves extract and evaluating its clinical moisturizing efficacy. The formulations containing sodium acrylates/ Beheneth-25 methacrylate Crosspolymer (and) hydrogenated polydecene (and) lauryl glucoside and 0.5% of extract were prepared. The extract was considered as non-irritating through skin irritant tests. The stability testing was carried out in different conditions for 90 days. The skin hydration was measured by capacitance measurement and transepidermal water loss using biophysical techniques. The results indicate that the formulation containing 0.5% of extract increased the hydration of the stratum corneum up to 5 h after application on the forearm. The transepidermal water loss was reduced when compared to the untreated area and placebo area. Therefore, we can conclude that the increased skin hydration and protection of barrier function can be attributed to the K. brasiliensis extract. This research presents a new raw material from the Brazilian Caatinga biome and shows its possible application in the development of cosmetic products.