Dose related pharmacokinetics of of loxacin in healthy volunteers

OBJECTIVE: To evaluate the pharmacokinetic profile of ofloxacin in healthy volunteers after single oral doses of 600 and 800 mg. DESIGN: Seven healthy volunteers were administered 600 and 800 mg of ofloxacin on two occasions with an interval of one week. Paired samples of blood and saliva were collected after 1, 2, 3, 6, 9, 12, 24, 32 and 48 hours post-dose. Urine samples were collected over a period of 0-6, 6-12 and 12-24 hours. Concentrations of ofloxacin in plasma, saliva and urine were assayed by high performance liquid chromatography. RESULTS: Increases of 22% in peak plasma concentration (C-max) and 40% in area under the concentration-time curve (AUC(0-24)) were observed with the 800 mg dose. The other parameters, namely time to attain C-max, half-life, the apparent volume of distribution, plasma and renal clearance and percentage of dose excreted in urine over 24 hours were independent of doses. The mean ratios of the concentration in saliva to the concentration in plasma ranged from 0.4-0.6, and the correlation coefficient was 0.94. CONCLUSIONS: Dose proportionality was observed in C-max and AUC(0-24) when 600 and 800 mg doses of ofloxacin were given. Ofloxacin determined in saliva seems to be suitable for therapeutic drug monitoring.