Biophysical analysis of prototype microbicidal gels

The objective of this study was to evaluate the distribution and retention (deployment) of four prototype vehicles for delivery of prophylactic microbicides against vaginal HIV transmission. Study gels were created with different molecular compositions, producing different biophysical properties governing vaginal deployment. The study employed three techniques: direct rheological measurement of gel properties, direct observation of gel surface coating erosion, and dissolution by a vaginal fluid simulant, and mathematical modeling of gel squeezing flow processes. Results suggest significant differences in extent of vaginal coating after gel application and in erosion of these gel layers due to contact with ambient vaginal fluid and shearing. The relationships between gel rheological properties, coating flow and erosion of coating were not always anticipated from differences in gel molecular composition.