Bioequivalence study of two oral tablet formulations containing tenofovir disoproxil fumarate in healthy volunteers.

Tenofovir disoproxil fumarate (TDF, CAS 147127-20-6) is a nucleotide reverse transcriptase inhibitor which is indicated in combination with other antiretroviral agents for the management of HIV-1 infection. The objective of this study was to compare the rate and extent of absorption and to assess the bioequivalence between a new pharmaceutical equivalent tablet formulation containing 300 mg of TDF and the innovator product. A randomized, single-center, open-label, single-dose, two-way crossover bioequivalence study in 40 healthy adult subjects was conducted. Dosing was separated by a wash-out period of 14 days. Blood samples were collected over 48 h and plasma levels of tenofovir (TFV) were determined by a validated HPLC assay. Rate and extent of absorption were similar between products. The 90% confidence interval (CI) of the ratio of the geometric means for log-transformed C(max), AUC(last) and AUC(inf) values were used to assess bioequivalence between the two formulations using the equivalence interval of 80 and 125%. In healthy subjects, the point estimate and 90% CI of the ratios of C(max), AUC(last) and AUC(inf) values were 0.99 (0.92-1.02), 0.99 (0.95-1.03) and 0.93 (0.85-1.02), respectively. Both treatments exhibited similar tolerability and safety. It was concluded that the new pharmaceutical product was bioequivalent to the innovator.