1,2-DI-O-HEXADECYLGLYCERO-3-PHOSPHOCHOLIN ES WITH ETHYLENE-GLYCOL UNITS ADJACENT TO THE HEAD GROUP

We synthezised a number of racemic 1,2-Di-O-hexadecylglycero-3-phospho cholines with hydrophilic ethylenglycol units (EO)(n) (with n = 1-3) a djacent to the choline of the head group and studied their lyotropic p hase behaviour in excess water (50 weight%) by differential scanning c alorimetry (DSC). The behaviour of the compounds was compared with tha t of the unsubstituted rac-1,2-Di-O-hexadecylglycero-3-phosphocholin ( DHPC). Our results indicate that there is almost no difference in the phase behaviour and in the water adsorption after introduction of one EO-unit. In contrast to this, the compounds with two and three EO-unit s show a changed polymorphic behaviour with increased temperature, ent halpy and entropy of the main transition and a higher adsorption of wa ter.