Multiple phase equilibria in binary mixtures of phospholipids.

Approximate phse diagrams describing lateral phase separations are given for binary mixtures of dimyristoyl phosphatidylcholine with dipalmitoyl phosphatidylcholine, distearoyl phosphatidycholine, and dipalmitoyl phosphatidylethanolamine. These diagrams are based in part on freeze-fracture electron microscopic data. These phase diagrams represent an improvement over previous studies in that both solid phses (Pbeta' and Lbeta') of the phosphatidylcholines are included. Further consideration is given to the problem of binary mixtures in which there are two Pbeta' phases that do not form a continuous range of solid solutions.