Liposomal Antioxidants for Protection against Oxidant-Induced Damage
Preparation of liposomal-N-acetylcysteine (L-NAC). L-NAC is prepared from a mixture of DPPC and NAC in a 1 : 1 molar ratio by a dehydration-rehydration method. The lipids are dissolved in chloroform in a round-bottomed flask and dried at 45°C with a rotary evaporator. The lipid film is dried with nitrogen to eliminate traces of chloroform and hydrated with a solution of NAC and subsequently sonicated. Sonication is a simple method for reducing the size of liposomes. Upon rehydration, free NAC is separated by high-speed centrifugation (24400 g at 4°C, for 30 min), a step performed twice. At the end of this procedure, the liposomal vesicle size is usually below 200 nm mean diameter with an encapsulation efficiency of 35% NAC.