# Eye drop formulations for enhanced penetration of water soluble antibiotics to treat infections

> **NIH NIH R01** · JOHNS HOPKINS UNIVERSITY · 2024 · $471,413

## Abstract

PROJECT SUMMARY
About 70% of all ocular infections are caused by bacteria. Each year in the US alone, there are millions of
cases of bacterial keratitis and conjunctivitis. Fluoroquinolones are effective for both treatment and prevention
of these infections, and moxifloxacin is often the drug of choice due to higher intraocular bioavailability
compared to other fluoroquinolones. The newest fluoroquinolone, besifloxacin, has also shown to have some
advantages in treating resistant organisms, including methicillin-resistant Staphyloccocus species and
Pseudomonas species associated with contact lens-related keratitis. Regardless, antibiotic eye drops are
prescribed to be used at least three times per day, and up to once every hour for severe infections. As the
required number of doses per day increases, patient compliance, and thus, treatment efficacy, decreases.
Issues with adherence can lead to sight-threatening complications and potentially contribute to bacterial
resistance. Antibiotic eye drop formulations that are more effective with less frequent dosing are needed to
improve patient outcomes and quality of life and slow the development of bacterial resistance. While eye drops
dominate the ophthalmic market, achieving effective intraocular drug delivery via eye drops is quite
challenging. Tear production, reflexive blinking, and nasolacrimal drainage limit residence time, while
formulation and drug properties can further limit the potential for the rapid intraocular drug absorption needed.
We have developed a mucosal drug delivery technology that increases drug delivery and absorption across
mucosal barriers, termed the mucus-penetrating particle (MPP) technology. Here, we describe an innovative
approach for formulating water-soluble fluoroquinolone antibiotic salts into ion-paired drug-core
nanosuspensions. Our preliminary data demonstrates that a moxifloxacin-pamoic acid MPP nanosuspension
(MOX-PAM NS) provides improved prevention and treatment in a rat model of bacterial keratitis. Importantly,
once daily dosing with MOX-PAM NS was as good or better than three times daily dosing with the commercial
formulation, Vigamox. The goal is to develop eye drop formulations of both moxifloxacin and besifloxacin to
provide broad spectrum treatment options for gram-positive, gram-negative, and resistant bacterial infections.
In Aim 1, we will make further formulation changes in the eye drops to increase intraocular drug absorption and
screen for antimicrobial activity against commercial and clinical bacterial isolates. In Aim 2, we will characterize
the topical drug penetration and efficacy in treating bacterial keratitis in rats. In Aim 3, we will perform full
pharmacokinetic studies, treatment efficacy studies, and topical safety studies in rabbits, which have ocular
size and structure more similar to humans. We anticipate that a reduction in dosing frequency while
maintaining efficacy against a wide range of common bacterial pathogens will have a po...

## Key facts

- **NIH application ID:** 10880663
- **Project number:** 5R01EY033386-03
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** Laura Ensign
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $471,413
- **Award type:** 5
- **Project period:** 2022-09-30 → 2027-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10880663

## Citation

> US National Institutes of Health, RePORTER application 10880663, Eye drop formulations for enhanced penetration of water soluble antibiotics to treat infections (5R01EY033386-03). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10880663. Licensed CC0.

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