Corneal epithelial toxicity of antiglaucoma formulations: in vitro study of repeated applications

Eye Irritation Potential of Microglycine and Microglycine-Containing Ointments: An in vitro Study on Reconstructed Human Corneal Epithelium

Objective

To assess the eye tolerability of a buffered ophthalmic solution containing microglycine (sodium hydroxymethylglycinate, mwater^TM) in an in vitro model.

Materials and Methods

A multiple endpoint analysis (MEA) approach was applied to the reconstructed human corneal epithelium (HCE) model. Sodium hydroxymethylglycinate solution (0.04%) and two ophthalmic ointments containing microglycine (Protectorial, containing 0.02% of sodium hydroxymethylglycinate, and Edenight, containing 0.04% of sodium hydroxymethylglycinate) were investigated. The buffered solution and the ointments were tested on HCE after acute (one application in 24 hrs, followed or not by 16 hrs of recovery) or repeated (one application per day for three consecutive days) exposures; benzalkonium chloride (BAK) 0.01% and saline isotonic solution were used as positive and negative controls, respectively. Cellular viability, trans-epithelial electrical resistance (TEER), lactate dehydrogenase (LDH) release and histo-morphology were evaluated.

Results

BAK 0.01% toxicity in HCE was confirmed for the 24+16 hrs acute and repeated exposure protocols, while, after 24–hours acute treatment, only modifications of the superficial cell layer were visible compared with the negative control. Sodium hydroxymethylglycinate had a very good tolerability profile and a neutral impact on the corneal surface after acute or repeated exposure. The Protectorial and Edenight ointments preserved cell viability in the different exposure protocols, suggesting a good local tolerability profile. Modifications of the superficial layers were observed on histo-morphological analysis and confirmed by increased release of LDH after 24+16 hrs acute exposure (+65% and +76% for Protectorial and Edenight, respectively) and TEER values after 24+16 hrs and 72 hrs exposure protocols. These results were dependent on the ointments’ accumulation on the corneal epithelium due to their physical form (semi-solid) and lipophilic properties.

Conclusion

Sodium hydroxymethylglycinate, alone or as part of eye ointments, was found to be non-toxic after acute or repeated exposure in the reconstructed HCE model.

The safety of besifloxacin ophthalmic suspension 0.6 % used three times daily for 7 days in the treatment of bacterial conjunctivitis

BACKGROUND

Besifloxacin ophthalmic suspension 0.6 % (Besivance(®); Bausch & Lomb, Rochester, NY, USA) was approved by the FDA in 2009 for the treatment of bacterial conjunctivitis, with a recommended 7-day dosing regimen.

OBJECTIVE

The objective of this study was to compare the safety of besifloxacin ophthalmic suspension 0.6 %, administered three times a day for 7 days, with that of its vehicle.

METHODS

This randomized, multicenter, double-masked, vehicle-controlled, parallel-group study involved 518 patients ≥1 year of age with a clinical diagnosis of bacterial conjunctivitis. Patients were randomized 2:1 to treatment with besifloxacin 0.6 % ophthalmic suspension or vehicle, one drop in the infected eye(s) TID for 7 days. Main outcomes included the incidence and types of adverse events reported by the subject or observed by the investigator at each study visit.

RESULTS

Thirty-one ocular treatment-emergent adverse events (TEAEs) were reported by 28 subjects in the study eye; 19 occurred in 17/344 (4.9 %) besifloxacin patients, and 12 occurred in 11/170 (6.5 %) vehicle patients (p = 0.5362). Only two ocular events (mild instillation site reaction, one case in each group) were considered "definitely related" to study treatment. One event of self-limited dysgeusia in the besifloxacin group was considered definitely related to treatment; there were no other nonocular TEAEs considered related to treatment. There were no serious adverse events, and other safety outcomes (visual acuity, biomicroscopy, ophthalmoscopy) were unremarkable.

CONCLUSION

These findings indicate that besifloxacin ophthalmic suspension 0.6 % is safe in patients aged 1 year and older when used TID for 7 days.