Non-linear pharmacokinetics of ofloxacin after a single intravenous bolus dose in pigs

Pharmacokinetics, urinary excretion and plasma protein binding of ofloxacin in water buffalo calves (Bubalus bubalis)

Pharmacokinetics and urinary excretion of an intravenous dose of 5 mg.kg-1 ofloxacin were investigated in water buffalo calves. Plasma concentrations of ofloxacin were determined by high-performance liquid chromatography. Ofloxacin was rapidly distributed from the central to the peripheral compartment as evidenced by a short distribution half-life (0.09 h ± 0.003 h) and high K12 (4.7 h(-1) ± 0.1 h(-1)), and was detected in plasma for 8 h. The large volume of distribution (2.48 L.kg(-1) ± 0.18 L.kg(-1)) obtained in this study indicated high distribution of ofloxacin in water buffalo calves. The elimination half-life, the area under the plasma drug concentration-time curve and total body clearance were 2.11 h ± 0.13 h, 6.20 µg.mL(-1) ± 0.23 µg.mL(-1).h and 0.81 mL.kg(-1).h(-1) ± 0.03 mL.kg(-1).h(-1), respectively. About 18.7% of administered drug was bound to plasma proteins and approximately 32.5% of the administered dose was recovered in urine within 48 h. The results of the study indicated a favourable pharmacokinetic profile of ofloxacin in water buffalo calves, which suggests that ofloxacin may be effective against urinary pathogens in this species.

Pharmacokinetics of ofloxacin in broiler chicken

Pharmacokinetics of ofloxacin, a fluoroquinolone antimicrobial agent, was determined in broiler chickens after intravenous or oral administration of a single dose (10 mg/kg). Ofloxacin concentrations in plasma were determined using a high-performance liquid chromatography assay. Plasma concentration profiles were analyzed by the noncompartmental method. Elimination half-life and mean residence time of ofloxacin in plasma were 4.46 and 5.48 h after intravenous administration and 5.85 and 7.43 h, respectively, after oral administration. Maximal plasma concentration of 3.65 microg/mL was achieved at 1.25 h after oral administration. Apparent volume of distribution of 1.76 and 2.16 L/kg and total body clearance of 4.96 and 4.5 mL/min/kg were obtained following intravenous and oral administration, respectively. The oral bioavailability of ofloxacin was 110.01%. Ofloxacin was found to be more rapidly absorbed, widely distributed and more quickly eliminated than other fluoroquinolones in broilers. Based on these kinetic parameters, a dosage of 10 mg/kg given orally every 24 h can be recommended for the treatment of bacterial infections with MIC90 < 0.3 microg/mL.

PLASMA CONCENTRATIONS OF ENROFLOXACIN AFTER SINGLE-DOSE ORAL ADMINISTRATION IN LOGGERHEAD SEA TURTLES (CARETTA CARETTA)

Plasma concentrations and pharmacokinetics of enrofloxacin were determined in 12 loggerhead sea turtles (Caretta caretta) after oral administration. Six turtles in group 1 and group 2 received enrofloxacin at 10 mg/kg and 20 mg/kg of body weight, respectively. Blood was collected from the cervical sinus before administration and at timed intervals up to 168 hr following administration. Plasma concentrations of enrofloxacin were determined using a microbiologic assay. The mean peak plasma concentration (Cmax) was 4.07 microg/ml and 21.30 microg/ml for groups 1 and 2, respectively. Plasma levels were detectable at 168 hr postadministration, with mean values of 0.380 microg/ml for group I and 2.769 microg/ml for group 2. The mean elimination half-life for enrofloxacin was 37.80 hr for group I and 54.42 hr for group 2. These findings indicated that enrofloxacin is absorbed following oral administration in loggerhead sea turtles, and blood levels are maintained up to 168 hr following administration.