PECULIARITIES OF STRUCTURAL PHASE TRANSITIONS IN A SELF-ORGANIZING AOT/WATER/ISOPROPYL MYRISTATE SYSTEM UPON INTRODUCTION OF L-LYSINE

Abstract

New biocompatible microemulsion and liquid-crystalline sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/water/isopropyl myristate systems have been obtained for the delivery of drugs and physiologically active substances. A combination of dynamic light scattering and X-ray diffraction methods has been used to determine their structural and size characteristics. The Primus and SasView software packages have been employed to simulate the shape and arrangement of particles as depending on AOT content. It has been shown that, as the concentration of the surfactant increases, the shape of micelles varies from spherical to cylindrical, and, at high concentrations, a structural phase transition occurs with the formation of a liquid-crystalline phase. The influence of a model bioactive compound, L-lysine, on the size and structure of the system has been studied. It has been revealed that the addition of the amino acids to the samples leads to an increase in the microemulsion droplet size, and, in the case of the liquid-crystalline phase, to the disintegration of the hexagonal packing into individual cylinders. The results obtained can be useful for the analysis of the mechanisms of L-lysine release from the AOT/water/isopropyl myristate transport system.