Online citations, reference lists, and bibliographies.
← Back to Search

Comparison Of Concentration-time Profiles Of Levobunolol And Timolol In Anterior And Posterior Ocular Tissues Of Albino Rabbits.

A. Acheampong, A. Breau, M. Shackleton, W. Luo, S. Lam, D. Tang-Liu
Published 1995 · Medicine

Cite This
Download PDF
Analyze on Scholarcy
The potential effects of anti-glaucoma drugs, such as levobunolol and timolol, on blood flow in the posterior segment of the eye are of great interest in terms of changes in optic nerve head perfusion and prevention of visual field loss. These effects are related to the rate and extent of their absorption into the site of action. In this study, the concentrations of timolol and levobunolol in the aqueous humor, iris-ciliary body, vitreous humor, choroid-retina, and optic nerve were compared following instillation of a single drop of 0.5% ophthalmic solutions into albino rabbit eyes. Tissue drug and metabolite concentrations were measured by liquid chromatography-mass spectrometry. Dihydrobunolol (DHB) is an equipotent metabolite of levobunolol. In the anterior segment of the eye, levobunolol plus DHB concentrations were higher than timolol concentrations in aqueous humor and were comparable to those of timolol in iris-ciliary body. However, in the choroid-retina and optic nerve, timolol concentrations were greater than those of levobunolol plus DHB. Overall, the study demonstrates comparable concentrations of levobunolol and timolol in the anterior section of the eye. The low availability of levobunolol in the posterior segment as compared to timolol may be a key advantage for levobunolol in producing less adverse effect on blood flow in the choroid-retina and optic nerve.

This paper is referenced by
In vitro cytotoxicity of eight beta-blockers in human corneal epithelial and retinal pigment epithelial cell lines: comparison with epidermal keratinocytes and dermal fibroblasts.
H. I. Cheong (2008)
Singlet molecular oxygen generation and quenching by the antiglaucoma ophthalmic drugs, Timolol and Pindolol.
S. Criado (2002)
Influence of Intraocular Pressure Lowering Medication on Vascular Supply
G. Holló (2003)
Cystoid macular edema associated with latanoprost therapy in a case series of patients with glaucoma and ocular hypertension.
S. Moroi (1999)
Timolol Concentrations in Rat Ocular Tissues and Plasma After Topical and Intraperitoneal Dosing
A. Y. Tan (2002)
Effects of topical nipradilol, a beta-blocking agent with alpha-blocking and nitroglycerin-like activities, on aqueous humor dynamics and fundus circulation.
M. Kanno (1998)
Latanoprost and clinically significant cystoid macular edema after uneventful phacoemulsification with intraocular lens implantation
P. C. Yeh (2002)
Co-Delivery of Timolol and Brimonidine with a Polymer Thin-Film Intraocular Device.
Karen E. Samy (2019)
Cyclodextrin formulation of dorzolamide and its distribution in the eye after topical administration.
H. Sigurdsson (2005)
The effects of antiglaucoma and systemic medications on ocular blood flow
V. P. Costa (2003)
Topical drug delivery to the posterior segment of the eye: anatomical and physiological considerations.
T. Loftsson (2008)
Effect of topical timolol on tissue circulation in optic nerve head.
Y. Tamaki (1997)
Timolol increased retrobulbar flow velocities in untreated glaucoma eyes but not in ocular hypertension.
I. Bergstrand (2001)
Effects of timolol and betaxolol on choroidal blood flow in the rabbit.
J. Kiel (1998)
Human lens epithelial cell damage and stimulation of their secretion of chemical mediators by benzalkonium chloride rather than latanoprost and timolol.
Y. Goto (2003)
Introductory comments on potential differences between beta-blockers in the treatment of open-angle glaucoma.
S. Drance (1999)
Topical and systemic absorption in delivery of dexamethasone to the anterior and posterior segments of the eye.
H. Sigurdsson (2007)
Topical nipradilol: effects on optic nerve head circulation in humans and periocular distribution in monkeys.
K. Mizuno (2002)
Molecular design for enhancement of ocular penetration.
Yoshihisa Shirasaki (2008)
Injectable drug depot engineered to release multiple ophthalmic therapeutic agents with precise time profiles for postoperative treatment following ocular surgery.
M. Mohammadi (2018)
Cyclodextrins in eye drop formulations: enhanced topical delivery of corticosteroids to the eye.
T. Loftsson (2002)
Effects of antiglaucoma drugs on blood flow of optic nerve heads and related structures
C. Mayama (2012)
Effect of gold nanoparticles on timolol uptake and its release kinetics from contact lenses: In vitro and in vivo evaluation.
Furqan A. Maulvi (2019)
Novel Triamcinolone Acetonide-Loaded Liposomal Topical Formulation Improves Contrast Sensitivity Outcome After Femtosecond Laser-Assisted Cataract Surgery
Alejandro Gonzalez-De la Rosa (2019)
Semantic Scholar Logo Some data provided by SemanticScholar