Exploring novel type of lipid-bases drug delivery systems that contain one lipid and one water-soluble surfactant only.

None of transitional lipid-based drug delivery systems (LBDDS) includes compositions containing one lipid and one water-soluble surfactant that form stable microemulsions. The conversion of liquid LBDDS to solid LBDDS has been limited by low drug loading. Previously, we have developed drug solid microemulsions containing one lipid and TPGS (a water-soluble surfactant) that achieved high drug loading and remarkably increased oral bioavailability. This study aimed to test if binary lipid systems (BLS), composed of one lipid and one water-soluble surfactant that form stable self-emulsifying microemulsions, is not an exclusive but widely applicable type of LBDDS for other lipids and surfactants and evaluate the influences of chemical structures of lipids and surfactants on microemulsions and solid microemulsions. We systemically identified new BLS by using a library of lipids and surfactants. Propylene glycol diesters and glycerol triesters were favorable for forming stable microemulsions with Tween 80, Cremophor EL, or TPGS. To the best of our knowledge, this is the first report exploring and confirming that the BLS is a new addition to traditional LBDDS, provides a promising option for researchers, and has the potential to increase drug loading to facilitate the development of solid microemulsions.