The disposition of suxibuzone in the horse.

A

Disposition of human drug preparations in the horse, III : orally administered alclofenac

Concentrations of the non-steroidal anti-inflammatory drug (NSAID) alclofenac were determined by a sensitive high performance liquid chromatographic procedure in plasma and urine of horses following oral administration of a dose of 3 g. In plasma, alclofenac was present in detectable concentrations for 72 h. The plasma disposition in individual horses was best described by a bi-compartmental model with two successive rate constants ka1 = 0.05 +/- 0.06 h-1 and ka2 = 0.06 +/- 0.01 h-1. Alclofenac half-lives t1/2alpha and t1/2beta were 1.0 +/- 0.8 h and 6.9 +/- 1.5 h, respectively. Maximal concentrations (38.9 +/- 16.2 mug/ml) were obtained after 8.5 +/- 2.4 h. Alclofenac was detected in urine for at least 48 h after dosing. The percentage of the dose excreted as unchanged alclofenac in 12 h was very low (0.68 +/- 0.19%), total (free + conjugated) alclofenac accounted for 2.16 +/- 0.55% of the dose