Topical SDZ GLC-756, a novel dopamine D-1 antagonist and D-2 agonist, lowers intraocular pressure in conscious rabbits.

This investigation was carried out to evaluate the effect of SDZ GLC-756, a novel dopamine D-1 antagonist and D-2 agonist, on intraocular pressure (IOP) in rabbits. A randomized, placebo-controlled, double-masked, crossover study with topical application of SDZ GLC-756 eyedrops [0.015% (n = 10), 0.03% (n = 10), 0.0625% (n = 10), 0.125% (n = 9), 0.25% (n = 10), 0.5% (n = 14)] and vehicle alone (placebo-control) to the right eye was performed in New Zealand White rabbits. The contralateral eye received no treatment. IOP was measured using a pneumatonometer. Topical SDZ GLC-756 significantly lowered IOP in a dose-dependent manner (maximal IOP-lowering effect 1 approximately 2 hours after administration) in the treated eye and, to a lesser extent, in the contralateral eye. The duration of action was approximately 4 hours. The simultaneous D-1 antagonistic and D-2 agonistic properties of SDZ GLC-756 may provide a new pharmacological approach to the treatment of glaucoma, which deserves further investigation.