Method of accessing mixed lipid transport properties of a drug

A method of assessing the mixed lipid transport properties of a drug in a mixed lipid composition comprising the steps of:

• a. providing a mixed lipid composition comprising:
• i. at least one non-esterified fatty acid;
• ii. at least one monoglyceride which is a monoester of glycerol and a fatty acid;
• iii. lysophosphatidylcholine;
• and
• iv. said drug;
• wherein the molar ratio of said at least one non-esterified fatty acid to said at least one monoglyceride is from about 2:1 to about 1:2, and the amount of said lysophosphatidylcholine is from about 1.0 mole percent to about 30.0 mole percent of the total lipid formulation;
• b. placing the mixed lipid composition of at least one non-esterified fatty acid, at least one monoglyceride, lysophosphatidylcholine and drug in an aqueous environment containing bicarbonate;
• c. subjecting said mixed lipid composition to shearing forces sufficient to cause formation of mixed lipid-bicarbonate colloidal particles which incorporate the drug;
• d. applying said particles to a size exclusion chromatography column;
• e. eluting said particles from said size exclusion chromatography column;
• and
• f. determining the elution profiles of the free drug and the drug incorporated into the particles;
• wherein drags eluting with said particles are considered to be stably transportable in the mixed lipid composition.