New CL drug delivery system for DED

Investigators from the Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, led by Francisco Javier Navarro-Gil, MD, from the Department of Optometry and Vision reported that contact lenses soaked in melatonin analogs may be able to address aqueous tear deficient dry eye disease.¹

The researchers tested their idea in a rabbits using five commercially available hydrogel contact lenses to serve as a delivery system for melatonin analogs; the goal was to determine the in vivo secretagogue effect of contact lenses loaded with melatonin analog.

The contact lenses were soaked with melatonin or melatonin analog solutions (1 mM) for 12 hours before instillation in the animals, they explained.

Three compounds were tested: 5-methoxycarbonylamino-N-acetyltryptamine (5MCA-NAT), N-butanoyl-2-(9-methoxy-6H-isoindolo [2,1-a]indol-11-yl) ethanamine (IIK7) and agomelatine. Three commercially available silicone hydrogel contact lens materials [Balafilcon A (PureVision 2, Bausch & Lomb), Comfilcon A (Biofinity, CooperVision), and Stenfilcon-A (MyDay, CooperVision)], and two conventional hydrogel contact lens materials [Omafilcon A (Proclear, CooperVision) and poly(2-hydroxyethyl methacrylate), p-HEMA, (Veraflex T, Interlenco)] were evaluated.

The lenses loaded with IIK7 did not have an adequate load of this compound. The conventional hydrogel lenses loaded with agomelatine released more agomelatine than silicone lenses (16% to 33% more).

The investigators found that the lenses made of silicone materials facilitated more effective delivery of 5-MCA-NAT than the lenses made of conventional materials (24% to 29%). The contact lenses loaded with agomelatine or 5-MCA-NAT in rabbits triggered higher tear secretion than the corresponding eye drops (78% and 59% more, respectively).

Based on their results, the authors believe that contact lenses soaked with melatonin secretagogues can be effective drug-delivery systems in the cornea and could be valuable tools for managing aqueous dry eye disease.

“The results indicated that agomelatine/5-MCA-NAT-loaded contact lenses triggered a potent and higher tear secretagogue effect than melatonin analog eye drops. Secretagogues are one of the most prominent agents to treat aqueous deficient dry eye disease because of the improvements in tear, mucin, and lipid secretion and thus tear film stability. Consequently, melatonin analog-loaded contact lenses could be an alternative to the current topical secretagogues against dry eye disease,” they concluded.

Reference

1. Navarro-Gil FJ, Huete-Toral F, Olalla Domínguez-Godínez C, et al. Contact lenses loaded with melatonin analogs: a promising therapeutic tool against dry eye disease. J Clin Med 2022;11:3483; https://doi.org/10.3390/jcm11123483.