Innovative sensory methods to access acceptability of mixed polymer semisoft ovules for microbicide applications

Vaginal microbicides are a promising means to prevent the transmission of HIV, empowering women by putting protection under their control. We have been using gel technology to develop microbicides in the intermediate texture space to overcome shortcomings of current solid and liquid forms. We recently formulated semisoft ovules from mixed polymer combinations of carrageenan and Carbopol 940P to overcome some of the flaws with our previous generation of formulations based solely on carrageenan. To determine the user acceptability of the reformulated gels, women first evaluated intact semisoft ovules before evaluating ovules that had been subjected to mechanical crushing to simulate samples that represent post-use discharge. Women then evaluated combinations of intact and discharge samples to understand how ovule textures correlated with texture of the resulting discharge samples. Carbopol concentration directly and inversely correlated with willingness to try for discharge samples and intact samples, respectively. When evaluating intact samples, women focused on the ease of inserting the product and preferred firmer samples; conversely, when evaluating discharge samples, softer samples that resulted in a smooth paste were preferred. Significant differences between samples were lost when evaluating pairs as women made varying trade-offs between their preference for ease of inserting intact ovules and acceptability of discharge appearance. Evaluating samples that represent different stages of the use cycle reveals a more holistic measure of product acceptability. Studying sensory acceptability in parallel with biophysical performance enables an iterative design process that considers what women prefer in terms of insertion as well as possibility of leakage.