 This is an open label comparative study of tenofovir gel and film in 10 healthy sexually active women without active female genital tract disorders. The women will receive a single dose of each formulation - tenofovir gel 1;equivalent to 40 mg in 4mls of gel and tenofovir film 1.3;40 mg - in a crossover study design to determine the pharmacokinetics of tenofovir in the blood, cervical tissue, and cervicovaginal fluid primary objective. Further, pharmacodynamics will be assessed using cervical tissue in an ex vivo HIV biopsy challenge, and safety will be determined by assessment of adverse events following a single dose of each formulation secondary objective. The primary endpoint will be to determine concentrations of tenofovir TFV and its metabolite, tenofovir diphosphate TFV-DP, in plasma, tissue homogenates, and cervicovaginal fluid. Secondary endpoints will be determined by assessing concentrations of HIV p24 protein from explant aliquot samples up to 21 days post-infection ex vivo, and by determination of Grade 2 or higher adverse events deemed related to study product. 