A major problem in the use of timolol in glaucoma therapy is its relatively high incidence of cardiovascular and respiratory side effects. This report presents preliminary evidence for the feasibility of a prodrug approach to minimize systemic absorption of timolol using a reduced topical dose made possible by improved corneal drug penetration. The results indicate that the O-acetyl, propionyl,...

We have established an ocular pharmacokinetic/pharmacodynamic (PK/PD) model for a beta-adrenergic antagonist, timolol, after instillation into rabbits. Timolol concentrations were determined by HPLC in the tear fluid, aqueous humor, cornea, and iris-ciliary body after instillation or ocular injection into the anterior chamber of the eye in rabbits. In addition, intraocular pressure (IOP) measur...

The hypotensive effect of intramuscular or intravenous acetazolamide with frequent instillation of 2% or 4% pilocarpine in polyvinyl alcohol, or with single drops of pilocarpine in polyvinyl alcohol or oily vehicles, and the hypotensive effect of topical timolol alone and together with pilocarpine was investigated in the treatment of acute closed-angle glaucoma in 75 patients (81 eyes). The res...

Timolol maleate is a non-selective beta-adrenergic receptor blocking agent. Its chemical name is (-)-1-(tert-butylamino)-3-[(4-morpholino-1,2,5-thiadiazol-3-yl)oxy]-2-propanol maleate (1:1) (salt). Timolol maleate possesses an asymmetric carbon atom in its structure and is provided as the levo-isomer. The optical rotation of timolol maleate is: 25° [α] in 1.0N HCl (C = 5%) = -12.2° (-11.7° to -...

describing drug disposition in eye compartments to simulate disposition of clonidine after topical (eye drop) administration [1]. This example extends the methodology to describe the disposition of timolol in different eye tissues and plasma after topical administration. Timolol is a nonselective beta-adrenoceptor antagonist used to lower intraocular pressure (IOP) [2]. A serious disadvantage o...

Purpose: Compared to the well-documented cytotoxic quaternary ammonium Benzalkonium chloride (BAK), Polyquaternium-1 (PQ) is proposed to be safer for the ocular surface. Using an established acute rabbit toxicological model, we tested the toxicological profiles of three topical antiglaucoma treatments: two commercially available fixed combinations of latanoprost/timolol containing 0.020% BAK (l...

men. After two weeks of placebo, 11 men received timolol 30 to 60 mg daily, and nine men received propranolol, 240 to 480 mg daily, for five weeks in a double-blind randomized study. The 20 men then received placebo again for two weeks. Right heart catheterization was performed in all 20 patients after two weeks of the first placebo and after five weeks of timolol or propranolol. Equipotent dos...

OBJECTIVE To determine possible differences in the intraocular pressure (IOP) and ocular pulse amplitude (OPA) lowering capacity of the fixed drug combinations dorzolamide/timolol and brinzolamide/timolol. METHODS In this cross-sectional study, one of the eyes of 25 healthy subjects was randomly assigned to treatment with dorzolamide/timolol and the other eye with brinzolamide/timolol. After ...

The study purpose was to evaluate preventive use of dorzolamide-timolol ophthalmic solution (Cosopt) during laparoscopic surgery with the patient in steep Trendelenburg (ST) position. Periorbital swelling, venous congestion, and elevated intraocular pressure (IOP) may produce low ocular perfusion. Prompt IOP reduction is important because 30- to 40-minute episodes of acute IOP elevations can re...

AIM To evalaute the effect of fixed-combination latanoprost 0.005%/timolol maleate 0.5% and dorzolamide hydrochloride 2%/timolol maleate 0.5% on postoperative intraocular pressure after phacoemulsification cataract surgery. METHODS This study is a prospective, randomized, double-masked and placebo-controlled. The study included 90 eyes of 90 patients which were scheduled to have phacoemulsifi...