Phase behaviour of aqueous systems of enzymatically modified phosphatidylcholines with one hexadecyl and one hexyl or octyl chain

Phosphatidylcholines composed of a hexadecyl chain in the 2-position and a hexyl or octyl chain in the l-position (C₆C₁₆PC or C₈C₁₆PC) were prepared from dipalmitoylphosphatidylcholine by lipase-catalyzed transesterification; the aqueous phase properties of the products were examined. In the C₈C₁₆PC-water system, a lamellar liquid-crystalline phase was dominant. Like all long-chain phosphatidylcholines studied earlier, a liposomal dispersion was formed in the presence of excess water. In the C₆C₁₆PC system, a new type of phase behaviour was observed; at high water content, an L₃ phase was formed.