Penetration of metronidazole and tinidazole into the aqueous humor in man

500 mg of metronidazole or tinidazole were given as a 20-min infusion each to 10 patients who were hospitalized for elective cataract extraction. Metronidazole and tinidazole concentrations in aqueous humor were 5.2 +/- (SE) 0.5 and 5.3 +/- 0.7 micrograms/ml, respectively, 20-70 min after the end of the infusion. Aqueous humor/serum concentration ratios were 0.38 and 0.47 on the average for metronidazole and tinidazole, respectively.