Effect of 15-keto latanoprost on intraocular pressure and aqueous humor dynamics in monkey eyes.
OBJECTIVE
To compare the ocular hypotensive effects of 15-keto latanoprost (KL) with the commercial preparation of latanoprost (Xalatan; Pfizer, New York, NY) in monkey eyes with laser-induced unilateral glaucoma and to evaluate the effects of topical 0.005% KL on aqueous humor dynamics in normal monkey eyes.


METHODS
Intraocular pressure (IOP) was measured hourly for 6 hours beginning at 9:30 AM on day 1 (untreated baseline); day 2 (vehicle only); and treatment days 1, 3, and 5 (topical, 30 microL of study drug) in the glaucomatous eyes of four to eight monkeys with unilateral laser-induced glaucoma. KL concentrations of 0.0001%, 0.001%, and 0.01% and latanoprost at 0.005% were studied separately, with a minimum washout period of 2 weeks between studies. Tonographic outflow facility (C) and fluorophotometric aqueous humor flow rates (F) were measured in nine normal monkeys before and after a single topical dose of 0.005% KL in one eye, with a vehicle-only control in the fellow eye.


RESULTS
When applied once daily to glaucomatous monkey eyes, all three concentrations of KL and a 0.005% concentration of latanoprost produced significant (P < 0.05) reductions in IOP, with the maximum reduction on treatment day 5, regardless of the drug or concentration studied. The maximum reduction (P < 0.001) from vehicle-only baseline IOP was (mean +/- SEM) 3.0 +/- 0.3 mm Hg (9%) for 0.0001% KL, 7.6 +/- 0.6 mm Hg (23%) for 0.001% KL, 6.3 +/- 0.4 mm Hg (18%) for 0.01% KL, and 6.6 +/- 0.6 mm Hg (20%) for 0.005% latanoprost. After application of a single dose of 0.005% KL in nine normal monkey eyes, neither C nor F was altered (P > 0.80) when compared with untreated baseline values or vehicle-treated control eyes.


CONCLUSIONS
The reduction in IOP produced by 0.001% KL was equivalent to, and at some measured time points, greater than the effect produced by 0.005% latanoprost. The IOP reduction by KL in normal monkeys appeared to have no effect on aqueous humor production or tonographic outflow facility and may thus indicate a drug-induced increase in uveoscleral outflow.
Wang
Rong-Fang
RF
Department of Ophthalmology, Mount Sinai School of Medicine of New York University, NY 10029, USA. rong-fang.wang@mssm.edu
Gagliuso
Donna J
DJ
Mittag
Thomas W
TW
Podos
Steven M
SM
D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage*; D001082:Aqueous Humor / Q000378:metabolism*; D015237:Dinoprost / Q000008:administration & dosage / Q000031:analogs & derivatives*; D004195:Disease Models, Animal; D005260:Female; D015590:Fluorophotometry; D005901:Glaucoma / Q000188:drug therapy* / Q000378:metabolism; D007429:Intraocular Pressure / Q000187:drug effects*; D000077338:Latanoprost; D008252:Macaca fascicularis; D011461:Prostaglandins F, Synthetic / Q000008:administration & dosage*; D014065:Tonometry, Ocular
D000959:Antihypertensive Agents; D011461:Prostaglandins F, Synthetic; C026528:15-ketoprostaglandin F2alpha; D000077338:Latanoprost; D015237:Dinoprost