Vesicants are known to induce inflammation and inflammatory processes that are associated with oxidative stress and the production of reactive oxygen (ROS) and reactive nitrogen oxide species (RNOS). Oxidative stress is a physiological condition in which the production of damaging free radicals exceeds the in vivo capacity of antioxidant protection mechanisms to prevent pathophysiology. ROS and RNOS can cause pathophysiology by directly damaging biomolecules such as lipids and proteins, thereby altering their function(s). We have found that oxidative stress and inflammatory agents play a key role in the toxicity of 2-chloroethyl ethyl sulfide (CEES). CEES is a monofunctional analog of sulfur mustard (bis-2-(chloroethyl) sulfide or HD) which is a bifunctional vesicant and a chemical warfare agent. Both HD and CEES are known to provoke acute inflammatory responses in skin. In particular, we have found that murine macrophages exposed to CEES have a decreased level of intracellular GSH, which is even further diminished in the presence of inflammatory agents. Pretreatment of the macrophages with N-acetyl cysteine (NAC) protects against the loss of intracellular GSH. NAC, the acetylated variant of the amino acid L-cysteine, is an excellent source of sulfhydryl (SH) groups. NAC is converted in the body into metabolites capable of stimulating GSH systhesis, promoting detoxification, and also acts directly as a free radical scavenger. NAC has also been used to protect against the lethality of HD. We have also found that stimulated RAW264.7 macrophages exposed to 500 microM CEES (24 hours) show increased levels of protein carbonyls. Protein carbonyls are perhaps the best index for assessing oxidative stress. These data suggest that antioxidant liposomes containing combinations of water and lipid soluble antioxidants may provide a unique therapeutic strategy for mustard gas by inhibiting the pathophysiology due to vesicant induced inflammation and oxidative stress. In this report we describe that characterization of large unilamellar antioxidant liposomes prepared using a M-110L Laboratory MicrofluidizerR Processor (at a rate of 270 ml/min at 18,000 PSI). The liposomes have been characterized by measuring: (1) particle size distribution using a dynamic light scattering; (2) liposome antioxidant (e.g., vitamin E content) and stability; (3) potential cytotoxicity using the MTT assay and; (4) cellular antioxidant uptake in RAW264.7 murine macrophage cell line; (5) ability to prevent CEES toxicity to NHEK adult keratinocytes. Our results with vitamin E-liposomes to date indicate that: (1) the vitamin E content of liposomes can alter their size distribution; (2) neither the tempoerature of storage (4oC or room temperature) nor the storage time (up to one month) influences the mean liposome diameter; (3) the vitamin E content of the liposomes decreases to very low levels when stored at room temperature for one month but this effect is much less pronounced at 4oC (4) the antioxidant liposomes are not cytotoxic to RAW264.7 cells; (4) the vitamin E content of RAW264.7 macrophages dramatically increases by incubation (for 24 hours) with vitamin E containing liposomes present in the medium at levels up from 15 to 55 microM (the range tested). Physiological levels of vitamin E are in the 10-30 microM range.