PHASE AND MISCIBILITY BEHAVIOR OF BINARY LIPID SYSTEMS

Differential scanning calorimetry was applied to study the phase diagrams of the following binary lipid systems: myristic acid (C13COOH) / pentadecanoic acid (C14COOH); palmitic acid methyl ester (C15COOMe) / heptadecanoic acid methyl ester (C16COOMe); palmitic acid methyl ester (C15COOMe) / stearic acid methyl ester (C17COOMe); palmitic acid methyl ester (C15COOMe) / arachidic acid methyl ester (C19COOMe). A distinct succession in the phase diagram types and phase regions was observed, according to the chemical structure of the mixing components. In the systems C13COOH/C14COOH; C15COOMe/C16COOMe and C16COOMe/ C17COOMe, both components are completely miscible in the low- and high-temperature phase. Contrasting with these three binary lipid systems, the system C15COOMe/ C14COOMe shows complete miscibility only in the high-temperature phase, but almost complete demixing in the solid state. In the phase diagram an incongruent melting "1:1 complex" is built up. This "complex" forms an eutectic mixture with the phase of C15COOMe and a peritectic system with C19COOMe. © 1990 Steinkopff.