.008% timolol ophthalmic solution. A minimal-effect dose in a normal volunteer model.

Area of Science:

• Ophthalmology
• Pharmacology

Background:

• Intraocular pressure (IOP) regulation is crucial for ocular health.
• Timolol maleate is a beta-blocker commonly used to manage glaucoma.
• Understanding the dose-response relationship of low timolol concentrations is important for therapeutic development.

Purpose of the Study:

• To evaluate the effect of low-concentration timolol maleate ophthalmic solutions on IOP.
• To assess the impact of these solutions on the diurnal variation of IOP in healthy individuals.

Main Methods:

• A double-masked, randomized, placebo-controlled, rising-dose, single-dose study design.
• Inclusion of healthy volunteers with normal intraocular pressure.
• Administration of timolol maleate ophthalmic solutions at concentrations of 0.008%, 0.025%, 0.08%, and 0.25%.

Main Results:

• A single 0.008% dose of timolol maleate demonstrated a statistically significant peak mean decrease in IOP of 1.8 mm Hg (12.8%) at 2 hours post-administration.
• This effect was minimal but notable compared to diurnal variations.
• A slight, non-statistically significant contralateral ocular hypotensive effect was observed with 0.25% timolol.

Conclusions:

• Low concentrations of timolol maleate, specifically 0.008%, can induce a measurable hypotensive effect in normal volunteers.
• This finding supports further investigation into ultra-low dose timolol formulations for IOP management.
• The study provides evidence for the ocular hypotensive potential of timolol maleate at very low concentrations.