Thin Film Flow of Polymeric Anti-HIV Microbicides: Comparison of 3-D Numerical and Experimental Simulations

In 2008, approximately 33.4 million people were living with HIV worldwide[1]. The rate of infection increases by about 5 million people per year[2], with a significant portion resulting from unprotected sex. A microbicide is a topical formulation that consists of a pharmaceutical agent suspended in a delivery vehicle (e.g. a polymeric liquid also called a “microbicide gel”), and could be a potential tool for preventing HIV transmission during intercourse. The vehicle itself can act as a physical barrier and, if designed with ideal physicochemical properties, might eliminate the need for a pharmaceutical agent altogether. In fact, a vehicle’s ability to coat the epithelium has been singled out as a crucial variable, which might dictate the microbicide’s efficacy[3]. Our overall objective is to develop an effective delivery vehicle that is capable of coating the vaginal epithelium under the influence of gravity, shearing, and compressive forces. The objective of this study is to numerically simulate the evolution of the 3-D free surface of a non-Newtonian fluid spreading under the influence of gravity. In addition, we aim to compare the spreading characteristics of the numerical model with experimental data, while incorporating similar initial conditions. Here, we present the advantages of accounting for lateral spreading in the numerical simulation.