The Role of Liposomal Antioxidants in Oxidative Stress

Abstract

Oxidative stress has been characterized by an elevation in the steady- state concentration of reactive oxygen species including superoxide anion, hydrogen peroxide, and hydroxyl radical. There is increasing evidence connecting oxidative stress with a variety of pathological conditions including cancer, cardiovascular diseases, chronic inflammatory disease, post-ischaemic organ injury, diabetes mellitus, xenobiotic/drug toxicity, and rheumatoid arthritis. A pharmacological strategy in preventing or treating oxidant-induced damage is by administering appropriate antioxidants. Evidence from several studies have shown that administration of antioxidants did not seriously modify the injurious actions of oxidants, an observation attributed mostly to their inability to cross cell membrane barriers and/or to their rapid clearance from cells. Recent advances in controlled delivery systems for drugs such as liposomes have generated an interest in their potential application for the prophylaxis or treatment of oxidant- induced injuries. The relative ease in incorporating hydrophilic and lipophilic therapeutic agents in liposomes; the properties of liposomes to protect therapeutic agents from inactivation; the possibility of directly delivering them to an accessible body site; and their relative non-immunogenicity and low toxicity have rendered the liposomal system highly attractive for drug delivery. This review focuses on the use of liposomes for the delivery of antioxidants in the prevention or treatment of several pathological conditions linked to oxidative stress.