Use of a novel non-steroidal anti-inflammatory drug in the horse

In a two-part cross-over experiment in six ponies, an acute inflammatory reaction was generated by injecting carrageenin solution into subcutaneously-implanted tissue-cages lined with fibrovascular granulation tissue. In each part of the cross-over, half of the ponies received a novel phenylpyrazoline anti-inflammatory agent (BW540C) orally and half received a placebo treatment. BW540C inhibited platelet cyclo-oxygenase for 24 h but the reductions in exudate eicosanoid concentrations were less pronounced. A significant suppression in the rise of surface skin temperature in BW540C-treated ponies paralleled drug-induced inhibition of thromboxane B2 bicyclic prostaglandin (PG) E2 concentrations at the inflamed site. The drug had no significant effect on 6-keto-PGF1 alpha, migrating leucocytes, lactate dehydrogenase or total protein in exudates. Maximum plasma concentrations of both compounds occurred 2 to 4 h after dosing and maximum exudate levels of drug and metabolite occurred at 12 h. Both compounds penetrated approximately three times less readily into exudate than into plasma.