Retinal and systemic pharmacokinetics of the anti-inflammatory drug cloricromene following oral administration in the rat and rabbit

The aim of this study was to evaluate the retina and plasma distribution of cloricromene, a coumarin derivative, and its active metabolite (MET) after an oral administration in rabbits and rats.A single dose of cloricromene was orally administered to rabbits (10 or 100 mg/kg) and to rats (100 mg/kg). Retina and plasma samples were collected at 15, 30, 60, and 90 min following administration. Drug concentrations in the retina and plasma were measured by high-performance liquid chromatography.As anticipated, only the active metabolite was found in all samples. The retina and plasma showed the same T(max); peak levels of the drug were achieved at 15 min in rats and at 30 min in rabbits. In rabbits, MET exposure was approximately dose-proportional in both retina and plasma between the 10- and 100-mg/kg dose. Substantial retinal exposure was observed in both the rat and rabbit, at exposures approximately nine- to sixteenfold lower in the retina than in plasma.The results showed that the active metabolite of cloricromene reached the retina after a single oral dose with exposures proportional to those in plasma. These data, along with the previously published potency data for cloricromene, suggest that cloricromene could be potentially useful in ischemic-retinal diseases where amelioration of blood flow and inflammation is desirable.