Laser irradiation of ocular tissues to enhance drug delivery

Scleral and corneal membranes represent substantial barriers against drug delivery to the eye. Conventional hypodermic needles-based intraocular injections are clinically employed to overcome these barriers. This study, for the first time, investigated a non-invasive alternative to intraocular injections by laser irradiation of ocular tissues. The P.L.E.A.S.E.(R) laser device was applied on excised porcine scleral and corneal tissues, which showed linear relationships between depths of laser-created micropores and laser fluences at range 8.9-444.4 J/cm(2). Deeper and wider micropores were observed in scleral relative to corneal tissues. The permeation of rhodamine B and fluorescein isothiocyanate (FITC)-dextran were investigated through ocular tissues at different laser parameters (laser fluences 0-44.4 J/cm(2) and micropore densities 7.5 and 15%). Both molecules showed enhanced permeation through ocular tissues on laser irradiation. Maximum transscleral permeation of the molecules was attained at laser fluence 8.9 J/cm(2) and micropore density 15%. Transcorneal permeation of rhodamine B increased with increasing either laser fluence or micropore density, while that of FITC-dextran was not affected by either parameter. The transscleral water loss increased significantly after laser irradiation then returned to the baseline values within 24 h, indicating healing of the laser-created micmpores. Laser irradiation is a promising technique to enhance intraocular delivery of both small and large molecule drugs.

Automated summary

This study explored a non-invasive alternative to intraocular injections using laser irradiation of ocular tissues. The experiment demonstrated enhanced permeation of molecules through ocular tissues on laser irradiation, showing potential for enhancing intraocular delivery of both small and large molecule drugs.