Saquinavir (Ro 31-8959) is a potent HIV protease inhibitor, is an antiretroviral drug used together with other medications to treat or prevent HIV/AIDS.

The AUC was not affected by grapefruit juice after intravenous administration, but it increased significantly from 76+/-96 (water, mean (s.d.) to 114+/-70 (microg l[-1] h) (grapefruit juice) after oral saquinavir. Similarly, the oral bioavailability of saquinavir increased by a factor of 2 with grapefruit juice (from 0.7% to 1.4%). In contrast, clearance, volume of distribution and elimination half-life of saquinavir were not affected by grapefruit juice. After oral, but not after intravenous administration, the plasma concentration-time curve showed a second peak after lunch irrespective of pretreatment, suggesting enhancement of absorption by food[1].

After an overnight fast, eight healthy volunteers were treated with either 400 ml grapefruit juice or water before intravenous (12 mg) or oral saquinavir (600 mg) was administered.?Serial blood samples were obtained over the following 24 h and standardized meals were served 5 and 10 h after the administration of saquinavir.?The plasma concentrations of saquinavir were determined by high-performance liquid chromatography and pharmacokinetic parameters were calculated by routine methods[1].