• We determined minocycline levels in human tears and plasma samples using high-performance liquid chromatography. In the first study, we determined the trough tear and plasma levels of minocycline in patients with active trachoma 24 hours after an oral dose. After a single dose of minocycline, the mean concentration of the drug in tear samples was 189 ± 58 ng/mL and corresponding plasma levels were 578 ± 290 ng/mL. In a second study, we monitored the pharmacokinetics of the drug in tear and plasma samples of healthy nonfasting adults. Tear and plasma samples were collected at 1 through 6, 12, 24, 48, 72, and 96 hours. The pharmacokinetics study revealed that 48 hours following a single 200-mg dose of minocycline, the mean tear level of minocycline was 68 ng/mL, which is above the in vitro minimal inhibitory concentration required for Chlamydia trachomatis and other susceptible organisms.
Tabbara KF, Cooper H. Minocycline Levels in Tears of Patients With Active Trachoma. Arch Ophthalmol. 1989;107(1):93-95. doi:10.1001/archopht.1989.01070010095034