Comparison of intraocular pressure lowering by topical and systemic carbonic anhydrase inhibitors in the rabbit.
Journal Article (Journal Article)
We compared the effect on intraocular pressure (IOP) of maximal doses of a topical carbonic anhydrase inhibitor (CAI) at acidic and alkaline pH where it is maximally effective with full systemic CA inhibition in ocular normotensive New Zealand Albino rabbits. Tonometric IOP levels were measured hourly during 3 hour control period. Topical MK-417 (pKa 5.8, 8.3), a close congener of MK-507 (Dorzolamide) was given as a 1.4% solution at pH 4.5 (n=6) and pH 9.2 (n=6). MK-417 was instilled to the left eye with the right eye used as an untreated control. One hour later methazolamide was given intravenously at 10 mg/kg, a dose known to give full inhibition of the enzyme. Control IOP (mm Hg) was 19.12+/-0.50. One hour following MK-417, the left eye IOP was 13.40 +/-0.70 (pH 4.5) and 13.25+/-0.70 (pH 9.2). The right eye pressure was unchanged. Methazolamide injection at this time gave no further drop in the left eye IOP at either pH. IOP in the right eye fell to 14.00+/-0.70 so that 2 hours after methazolamide injection, the 2 eyes had the same pressure. In conclusion, topical CAI in sufficient dose and correct pH yields IOP lowering equivalent to a maximally effective dose of systemic CAI in rabbits.
- Fanous, MM; Challa, P; Maren, TH
- February 1999
- Journal of Ocular Pharmacology and Therapeutics : the Official Journal of the Association for Ocular Pharmacology and Therapeutics
Volume / Issue
- 15 / 1
Start / End Page
- 51 - 57
International Standard Serial Number (ISSN)
Digital Object Identifier (DOI)
- United States