A double-masked, placebo-controlled evaluation of timolol in a gel vehicle.
We evaluated a topical formulation of timolol in an anionic heteropolysaccharide gellan gum (Gelrite). Fifty-five white patients with ocular hypertension entered a double-masked, placebo-controlled, four-period, incomplete block crossover study. After washout of any ocular hypotensive medications, the intraocular pressure of both eyes of all patients was measured at 0 (09:00 h), 2, 4, 6, 8, 12, and 24 h (diurnal baseline). Patients were then randomized to receive, at 2-week intervals, one drop of each of four of the six treatments in one eye (0.008% timolol gel, 0.1% timolol gel, placebo gel, 0.008% timolol solution, 0.1% timolol solution, and placebo solution). Fellow eyes received the appropriate placebo. As measured by least-squares means, adjusted for the unmedicated baseline diurnal values, there was a clear dose-response, with the 0.1% treatments being more effective ocular hypotensive agents than the 0.008% treatments, which in turn were more effective than the placebo treatments. Within each concentration at several observation points, the gel formulation elicited a 1-2-mm Hg greater efficacy than the solution. Gel-treated subjects had a greater incidence of blurred vision. We conclude that formulation of timolol with a gel may increase efficacy, and thus duration of action. This may possibly allow use of a lower concentration of timolol or a reduced frequency of instillation. Further evaluation in chronic dosing studies is justified.
Laurence
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*Baylor College of Medicine, Houston, Texas, daggerTulane School of Medicine, New Orleans, Louisiana, double daggerPrivate Practice, Louisville, Kentucky, section signKentucky Lions Eye Research Institute, University of Louisville, Louisville, Kentucky, and Departments of Ophthalmic Clinical Research and paragraph signBiostatistics, Merck Research Laboratories, West Point, Pennsylvania, U.S.A.
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Vogel
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Gross
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Haik
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Karp
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Koby
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Zimmerman
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