An intravaginal device that provides biologically active circulating concentrations of an aromatase inhibitor for at least about of 4 days. Liposome-based and a wax-based formulations were used to assess letrozole diffusion through bovine vaginal mucosa in a diffusion chamber study. The wax-based vehicle was selected for further development of a letrozole intravaginal device based on its steady release rate. The addition of a letrozole-containing gel coating improved initial absorption and hastened the increase on plasma concentrations of the active ingredient, while the letrozole-containing wax-based vehicle maintained prolonged delivery from the intravaginal device.