A 3% topical gel formulation of tenofovir disoproxil fumarate (TDF) for the treatment of human immunodeficiency virus (HIV) by experimental approach

Tenofovir disoproxil fumarate (TDF) is widely used in the treatment of HIV-infected adults and is also approved for the management of chronic hepatitis B in adults, where it is administered in combination with other antiretroviral agents. The present study employed Design-Expert® software to investigate the effects of Kolliphor®P188 (g), Methocel®K100 Premium LV (g), and polyethylene glycol (mL) concentrations on the drug release characteristics of a topical TDF gel formulation. Eight formulations, including three center points, were prepared and evaluated for physical appearance, spreadability, syringibility, washability, pH, and ex vivo drug release. The interactions between formulation variables and drug release were also assessed. The results demonstrated statistically significant differences among formulations (p < 0.05). The findings indicate that polymer concentration is a critical formulation variable that must be carefully optimized to achieve a topical gel with desirable performance characteristics.