Evidence map›Paper›PMID 40693711›Full record

ArticleTranslational vision science & technology2025

Topical Gel/Microsphere Eyedrop for Combined Delivery of Brimonidine and Timolol: A Comparative Study With Traditional Eye Drops in Rabbits.

Xin Fan, Phillip A Harding, Parissa Ziaei, Ahmad B Chaudhry, Raymond E West, Thomas D Nolin, Morgan V DiLeo

Abstract readComparative Study
In one paragraph

Article in Translational vision science & technology, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

7 authors.

Xin FanDepartment of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.
Phillip A HardingDepartment of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
Parissa ZiaeiDepartment of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.
Ahmad B ChaudhryDepartment of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.
Raymond E WestSmall Molecule Biomarker Core, Department of Pharmacy & Therapeutics, University of Pittsburgh, Pittsburgh, PA, USA.
Thomas D NolinSmall Molecule Biomarker Core, Department of Pharmacy & Therapeutics, University of Pittsburgh, Pittsburgh, PA, USA.
Morgan V DiLeoDepartment of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.

Funding

Virus Production and Manipulation of Protein/Gene Expression ModuleP30EY008098 · NEI · UNIVERSITY OF PITTSBURGH AT PITTSBURGH · PI Yuanyuan Chen · 1989 to 2026
$17.8M
Interdisciplinary Visual Sciences (IVS) Traininig ProgramT32EY017271 · NEI · UNIVERSITY OF PITTSBURGH AT PITTSBURGH · PI Marlene Behrmann, Paul R. Kinchington · 2008 to 2026
$3.6M
API 4000 QTRAPS10RR023461 · NCRR · UNIVERSITY OF PITTSBURGH AT PITTSBURGH · PI POLOYAC, SAMUEL M · 2007 to 2007
$487k
Small Molecule Biomarker Core: TSQ Altis LC-MS/MSS10OD028540 · OD · UNIVERSITY OF PITTSBURGH AT PITTSBURGH · PI NOLIN, THOMAS DOUGLAS · 2020 to 2020
$429k
NCRR NIH HHS S10 RR023461NEI NIH HHS P30 EY008098NEI NIH HHS T32 EY017271NIH HHS S10 OD028540
6 · The paper itself

Abstract

Purpose: Topical eye drops combining multiple antiglaucoma agents are often required when monotherapy fails to reduce intraocular pressure (IOP). However, their effectiveness is compromised by low bioavailability and poor patient compliance. To address these issues, we developed a novel gel/microsphere eye drop (GME) containing brimonidine and timolol, aimed at enhancing ocular bioavailability, reducing dosing frequency, and improving patient compliance. Methods: The GME system comprises separate formulations of brimonidine-loaded and timolol-loaded polymer microspheres within a thermoresponsive hydrogel, enabling simple off-the-shelf preparation. We examined the in vitro drug release, compared the biodistribution with traditional eye drops, and assessed pharmacodynamic effects in New Zealand white rabbits and Dutch Belted rabbits. Results: Brimonidine and timolol reached high concentrations in the aqueous and vitreous humor at 1 hour following eye drop administration, declining to nearly undetectable levels by 24 hours. The GME system at a similar dose extended the drug release to 27 days with initially lower drug levels but decreasing more slowly. The GME system also resulted in significantly lower plasma drug concentrations than eye drops, suggesting a reduced risk of systemic side effects. Neither the GME nor eye drops significantly reduced IOP in normotensive rabbits. Conclusions: The GME system presents a promising alternative to traditional eye drops for controlled drug release in ocular applications, enabling sustained drug delivery while minimizing systemic exposure and thereby potentially enhancing the safety and efficacy of ocular therapies. Translational Relevance: The GME system bridges basic research and clinical application by providing a controlled-release platform that sustains drug delivery, reduces systemic side effects, and enhances patient adherence.

Indexed as

Antihypertensive AgentsBrimonidine TartrateDrug Delivery SystemsGlaucomaTimololAdministration, TopicalAnimalsBiological AvailabilityGelsIntraocular PressureMaleMicrospheresOphthalmic SolutionsRabbitsTissue DistributionAntihypertensive AgentsBrimonidine TartrateGelsOphthalmic SolutionsTimolol

Identifiers

PMID40693711
PMCPMC12302038

What OpenQuestion holds

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LicenceCC BY-NC-ND
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Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.