A STUDY OF POLAR LIPID DRUG CARRIER SYSTEMS UNDERGOING A THERMOREVERSIBLE LAMELLAR-TO-CUBIC PHASE-TRANSITION

The polar insoluble, but swelling, lipid monoolein (glyceryl monooleate) forms a highly ordered cubic phase in excess water, which can be used to sustain the release of different types of drugs. One problem with the cubic phase, however, is its stiffness, and in order to make the administration of the cubic phase easier, precursors in the form of a lamellar phase were investigated. This phase undergoes a phase transition to the cubic phase on temperature increase; thus the lipid system formed in this way acts similar to in situ activated gel-forming polymer systems, e.g., Pluronic F-127, Gelrite and EHEC. Lipid drug carrier systems can be made from a wide variety of lipids. They can also be used in the application of a wide variety of drugs, and are very versatile as regards the site of administration. They can, therefore, be an interesting alternative to polymer systems.