Inhibition of prostaglandin-induced iritis. Topical indoxole vs indomethacin therapy

H. M. Spinelli and D. L. Krohn

Rat eyes pretreated with 10 microL of topically applied indoxole or 14C-indomethacin, both drugs as 0.5%, 1.0%, and 2.0% solutions in polysorbate 80, were subjected 60 minutes later to an intravitreal injection of 5 microL of 5.0% sodium arachidonate. Following a 30-minute interval, the iris vascular pattern was photographed under the same standardized conditions as in the preinjection control photographs. Comparison of the average diameters of preselected vessels showed indoxole to be more effective than indomethacin in inhibition of iris vascular dilation at all concentrations tested. Intracameral unbound indomethacin concentration was a whole order higher than that of indoxole after comparable doses. The difference in relative effect of the two drugs is neither a function of aqueous concentration nor of aqueous protein binding.