Ofloxacin in human serum, urine, and tear film after topical application

We evaluated the systemic absorption of ofloxacin eyedrops in humans and their availability in the tear film. Serum, urine, and tear film concentrations of ofloxacin were measured in 30 healthy women topically treated with 0.3% ofloxacin, in both eyes, four times daily for 10 1/2 days. Serum was collected before the first daily dose on days 1 and 11 and at 18 time points before the second dose. Maximum serum ofloxacin concentrations (1.89 +/- 1.13 ng/ml) after 10 1/2 days of topical dosing were more than 1,000 times lower than those reported after standard oral doses of 300 mg ofloxacin. Urine was collected for the 24-h period after the first daily dose on days 1 and 10. Topical ofloxacin was excreted in the urine primarily in unmodified form and recovery rates were significantly higher on day 10 (76.1 +/- 41.5%) than on day 1 (56.6 +/- 31.6%) (p less than 0.05). Both serum and urine data give evidence to accumulations of ofloxacin over a 10 1/2-day period. The low serum concentration at steady state suggests an extremely low potential for producing systemic effects. No systemic side effects attributable to topical ofloxacin were observed. Mild ocular irritation was reported by two patients while under treatment. Tears were collected 4 h after the first treatment on day 11 and at 5, 10, 20, 30, and 40 min after the second treatment.(ABSTRACT TRUNCATED AT 250 WORDS)