Protective effect of Coenzyme Q10 against oxidative damage in human lens epithelial cells by novel ocular drug carriers

The evaluation of N-trimethyl chitosan (TMC)-coated liposomes containing Coenzyme Q(10) as potential ophthalmic drug delivery system was carried out. Firstly, transcorneal permeation studies were conducted at 34 degrees C using a side-by-side diffusion apparatus. The transport process of the fluorescent marker, rhodamine B, across the corneal epithelium was visualized with confocal laser scanning microscopy. Secondly, the human lens epithelial cells (HLECs) were cultured without or with Coenzyme Q(10) followed by addition of H2O2. The cell viability and apoptosis were evaluated. The permeability coefficient for rhodamine B with TMC-coated liposomes increased more than two times in comparison with the value obtained for solution as control, from (0.42 +/- 0.018) x 10(5) cm s(-1) to (1.31 +/- 0.030) x 10(5) cm s(-1). Confocal laser scanning microscopy revealed that a TMC coating enhanced the transepithelial transport, dependent on the TMC concentration and contacting time. Coenzyme Q(10) elevated the cell viability and reduced the oxidative damage with the decreased percentage of a poptotic cells in a positive concentration-dependent manner. The ATP content of liposome-treated cells was increased about 2-fold compared with that of H2O2-treated cells. Together, our findings demonstrate that with the enhanced permeation effect of the TMC coating, Coenzyme Q(10)-loaded TMC-coated liposomes appear to be a promising ophthalmic drug delivery carrier with an efficacy in protecting HLECs against H2O2-induced oxidative damage. (C) 2010 Elsevier B.V. All rights reserved.