Maternal-fetal transfer of saquinavir studied in the ex vivo placental perfusion model

Objective: This study was undertaken to determine the placental transfer of the human immunodeficiency virus protease inhibitor saquinavir. Study Design: An ex vivo perfused human placental cotyledon model was used. Ten placental perfusion studies were performed, with concentrations of saquinavir in the maternal compartment ranging from 322 to 2197 ng/mL (within reference therapeutic ranges). Drug concentrations were determined by high-performance liquid chromatography. Results: The mean (± SD) fetal transfer rate of saquinavir was 1.8% ± 1.6%, and the mean (± SD) clearance index was 0.05 ± 0.05. A mean (± SD) of 1.6% ± 3.1% of the perfused saquinavir was retained by the cotyledon. The small amount of saquinavir that crossed the placenta corresponded to the fraction not bound to human serum albumin. Conclusion: The low rate of placental transfer of saquinavir suggests that use of this antiretroviral drug by pregnant women may not lead to significant exposure of the fetus. (Am J Obstet Gynecol 2001;185:178-181.)