Fig. 6.

Effect of tranylcypromine on the 2-hydroxylation of metronidazole by a panel of human liver microsomes. Human liver microsomes (0.05 mg microsomal protein) were incubated with metronidazole (100 μM) in 100-μl reaction mixtures at 37 ± 0.1°C in the presence or absence of tranylcypromine (6 μM), terminated after 60 minutes with 100 μl of methanol containing metronidazole-d4, and analyzed by HPLC/MS via direct injection, as described under Materials and Methods. Bars representing rates of 2-hydroxymetronidazole formation (inhibited and uninhibited by tranylcypromine) are the mean ± S.D. of three determinations.