Ocular drug targeting by liposomes and their corneal interactions

Abstract

Topical drug delivery is preferred in the eye to avoid under or over medication and undesired side effects of systemic administraion. In order to maintain adequate drug levels in ocular tissues, frequent drug installation is necessary in vision threatening conditions like glaucoma, corneal ulcers due to microbial infections, etc. Only apart of the installed drug reaches the aqueous humor and the rest of it is drained by the nasolacrimal duct. Positively charged liposomes have been found to enhance the penetration of drugs into the cornea. The present study was conducted to visualize the interaction of liposomes with the cornea. Briefly, positively charged liposomes entrapped with Carboxyfluorescein (CF), Propidium iodide (PI), Horseradish peroxidase (HRP), Biotin, Hydroxy benzimide (Hoechst No: 33258), and Ethoxy benzimide (Hoechst No: 33342) were prepared by sonication. Their size and shape were analysed by laser dynamic lightspectraand electron microscopy, respectively. The liposome encapsulated and free materials in buffer were instilled, in a volume of 20mul, into eyes of anesthetized albino rats. After 30min and 1h, the eyes were enucleated and quickly processed for cryosections of 3-5mum thickness. The interaction of liposome entrapped propidium iodide and HRPwas visualized on the outer epithelium of the cornea after specific processing.

Keywords::

• Propidium Iodide Carboxy Fluorescein Horseradish Peroxidase Liposome Cornea Ocular