Pharmacokinetics of levofloxacin after oral administration in normal and ketoprofen-treated sheep

The pharmacokinetics of levofloxacin was evaluated in female sheep following its single oral administration (3 mg kg) alone and on concomitant intramuscular (i.m.) administration of ketoprofen (3 mg kg). Levofloxacin concentration was determined using the High Performance Liquid Chromatography. Following oral administration of the drug, mean absorption rate constant (Ka) and mean elimination rate constant () were 1.21  0.19 and 0.13  0.01 h, respectively. The absorption (t1⁄2Ka) and elimination half-life (t1⁄2) were 0.75  0.23 and 5.25  0.21 h, respectively. The mean apparent volume of distribution (Vd(area)), area under plasma drug concentration-time curve (AUC(0 )) and area under first moment curve (AUMC) were 4.35  0.29 L/kg, 2.78  0.21 g.h/mL and 22.54  1.14 g.h/mL, respectively. The mean value of total body clearance (ClB) of the drug was 0.55  0.01 L/h/kg with mean residence time (MRT) of 8.18  0.28 h. The calculated mean value of mean absorption time (MAT) was 6.45  0.26 h. The levofloxacin concentrations from 8 to 24 hrs were significantly higher when ketoprofen was administered along with levofloxacin. However, pharmacokinetic parameters of orally administered levofloxacin were not significantly affected by concomitant administration of ketoprofen in sheep. Oral administration of levofloxacin at 3 mg/kg in sheep resulted in lower concentrations overall thus the drug may be efficacious against bacteria with lower MIC value (0.03