A comparison between iris-ciliary body concentration and receptor affinity of timolol.

Topical unilateral application of timolol reduces the IOP (intraocular pressure) of both the treated and the untreated eye. For this reason, a cental mechanism of action, in addition to the local one, has been suggested for the reduction of IOP by this drug. In this study timolol concentrations in the iris-ciliary body of the treated and untreated rabbit eyes were compared with pharmacologically active in vitro timolol concentrations. The drug concentration in the untreated eye too was found to be high enough to exert a local action.