The present invention provides a composition comprising or consisting of components (a) (i) at least one mono-alkanoyl glycerol ester, wherein alkanoyl is selected from C4 to C21 alkanoyl, preferably from octanoyl and decanoyl； and (b) (i) at least one compound selected from cholesterol, phosphatidyl cholines and phosphatidyl glycerols, wherein the acyl moieties of the phosphatidyl moieties are independently selected from C6 to C21 alkanoyl and C6 to C21 alkenoyl.
