Liposomes as a potential ocular delivery system of distamycin A

Liposomes containing Distamycin A (DA) may be clinically useful in the treatment of ocular HSV infections, especially in acyclovir-resistant HSV keratitis. This study evaluated the in vitro and in vivo performance of a topical controlled release liposomal formulation containing DA (DA-Lipo) aimed at reducing the toxicity of the encapsulated active agent and improving drug uptake by ocular tissues. The bioavailability of DA in the tear fluid and the DA uptake into the cornea were increased after instillation of DA-Lipo in rabbits, reaching the DA corneal concentration corresponding to IC50 values against HSV without any sign of transcorneal permeation of drug. DA-Lipo was definitely less cytotoxic then plain DA in rabbit corneal epithelial cells. These results provide new insights into the correlation between the in vitro data and the drug kinetics following ocular applications of liposomal vesicles.