Phase behaviour of polymer-grafted DPPC membranes for drug delivery systems design

DPPC dispersions containing DPPE with attached PEG of molecular masses 350, 2000 and 5000 were investigated by DSC in order to determine their phase behaviour and potential use as drug delivery systems. In comparison with previously obtained ESR data, DSC provided a definition of the lipid composition and temperature at which the vesicles are in a liquid crystalline phase. For DPPC DPPE-PEG 350 the composition range is at molar fractions 0<(chi PEG350)< 0.5. For DPPC DPPE - PEG 2000 the range of applicability is 0<(chi PEG2000)< 0.07 and for DPPC/DPPE - PEG 5000 system it is 0<(chi PEG5000)< 0.05.