[MK-507 (L-671 152): local tolerance and effectiveness of a new local carbonic anhydrase inhibitor in healthy probands].

A three-dose, randomized, double-blind parallel, placebo-controlled ocular tolerancy study was undertaken in 24 healthy, normal volunteers with two formulations of 2% MK-507 (L-671 152), a novel water-soluble, topical carbonic anhydrase inhibitor. In this study MK-507 was administered to humans for the first time. Subjects received 3 sequential drops of the test drug in one randomly selected eye (at 13:00, 14:00, and 14:10 o'clock): ten received 2% MK-507 formulated with 0.5% hydroxyethylcellulose (HEC); ten, 2% MK-507 with no HEC; two, vehicle with HEC; and two, vehicle without HEC. Local tolerance of 2% MK-507 was good with predominantly mild and transient local symptoms, somewhat fewer for the formulation without HEC. Significant lowering of intraocular pressure (IOP) by up to 7 mmHg was noted when comparing IOP 4 h and 5 h after the first dose with IOP 20 h and 19 h before the first dose in the treated eyes of subjects receiving MK-507. Slightly greater activity was noted when MK-507 was formulated with HEC.