Interspecies Differences in Tenofovir Alafenamide Fumarate Stability in Plasma.

Tenofovir (TFV) alafenamide fumarate (TAF) is an antiretroviral that has been evaluated in alternative drug delivery systems in several species. The ex vivo stability of TAF was evaluated, and TAF was stable in dog-, sheep-, and macaque-spiked plasma. A negative bias was observed in TAF recovery in rabbit-spiked plasma; there was complete loss of TAF and corresponding overestimation of TFV in rodent-spiked plasma. These data highlight considerations when evaluating TAF and TFV concentrations in preclinical studies.