Pharmacokinetics of ketorolac after intravenous and oral single dose administration in dogs

The pharmacokinetics of ketorolac (Toradol(TM)), a human non-narcotic, nons teroidal anti-inflammatory drug (NSAID) of the pyrrolo-pyrrole group, was s tudied in six mixed breed dogs of varying ages (1-5 years), The study was p erformed using a randomized crossover design, with each dog initially assig ned to one of two groups (intravenous (i.v.) or oral (p.o.)). Each group of three dogs received either the injectable or oral formulation of ketorolac tromethamine at 0.5 mg/kg. Serial blood samples were collected before and over 96 h following treatment, Samples were analysed by reverse phase HPLC. Individual ketorolac plasma concentration-time curves were initially evalu ated by computerized curve stripping techniques followed by nonlinear least squares regression. Following i.v. administration mean (+/-SD) pharmacokin etic parameters were: elimination half-life (t(1/2 beta))= 4.55 h, plasma c learance (Cl-p)= 1.25 (1.13) mL/kg/min, and volume of distribution at stead y state (V-ss) = 0.33 (0.10) L/kg, Mean (+/- SD) p.o. pharmacokinetic value s were: t(1/2 beta) = 4.07 h, time to reach maximum concentration (t(max)) = 51.2 (40.6) min, and p.o. bioavailability (F)= 100.9 (46.7)%. These resul ts suggest that the pharmacodisposition characteristics of a clinically eff ective 0.5 mg/kg i.v, or p.o. single dose of ketorolac tromethamine adminis tered to dogs is fairly similar to that observed in humans.