Effects of gamma irradiation on solid and lyophilised phospholipids

The effects of gamma irradiation (25 kGy) as a sterilisation method for pho spholipids (distearoylphosphatidylcholine and distearoylphosphatidylglycero l) were investigated. P-31-NMR revealed minor chemical degradation of the p hospholipids but lower dynamic viscosity and pseudoplasticity, lower turbid ity, higher diffusion constant, smaller size, more negative zeta potential and changes in the phase transition behaviour of the subsequently produced liposomes were observed. The observed changes could to some extent be expla ined by the irradiation-induced degradation products (distearoylphosphatidi c acid, fatty acids, lysophospholipids). (C) 1999 Elsevier Science Ltd. All rights reserved.