The rates of saquinavir metabolite formation were assessed with small-intestinal microsomes from 17 individual donors. Human small-intestinal microsomes were diluted with reaction buffer to give a final protein concentration of ∼0.05 mg/ml. Microsomes were warmed at 37°C in the presence of a NADPH-generating system for 3 min, and reactions were initiated by the addition of 10 μl of a 0.5 mM saquinavir solution in 1:1 acetonitrile:water to 0.99 ml reaction mixture. Reactions were terminated after 15 min by the addition of 1 ml of acetonitrile.

* Correlations between saquinavir metabolites were statistically significant, p < 0.001.