Ketoprofen (KTP) and meloxicam (MLX) are non-steroidal anti-inΒ£amatory drugs used extensively in veterinary medicine. The pharmacokinetics of these drugs were studied in eight dogs following a single oral dose of 1 mg/kg of KTP as a racemate or 0.2 mg/kg of MLX. The concentrations of the drugs in plasma were determined by high-performance liquid chromatography (HPLC). There were diΒ‘erences between the disposition curves of the KTP enantiomers, conΒ’rming that the pharmacokinetics of KTP is enantioselective. (S)-(+)-KTP was the predominant enantiomer; the S:R ratio in the plasma increased from 2.58+0.38 at 15 min to 5.72+2.35 at 1 h. The area under the concentration^time curve (AUC) of (S)-(+)-KTP was approximately 6 times greater than that of (R)-(^)-KTP. The mean (+SD) pharmacokinetic parameters for (S)-(+)-KTP were characterized as T max = 0.76+0.19 h, C max = 2.02+0.41 mg/ml, t1
2 el = 1.65+0.48 h, AUC = 6.06+1.16 mg.h/ml, V d /F = 0.39+0.07 L/kg, Cl/F = 170+39 ml/(kg.h). The mean (+SD) pharmacokinetic parameters of MLX were T max = 8.5+1.91 h, C max = 0.82+0.29 mg/ml, t1 2 l(z) = 12.13+2.15 h, AUC inf = 15.41+1.24 mg.h/ml, V d /F = 0.23+0.03 L/ kg, and Cl/F = 10+1.4 ml/(kg.h). Our results indicate signiΒ’cant pharmacokinetic diΒ‘erences between MLX and KTP after therapeutic doses.