Lipid carrier compositions with enhanced blood stability

1. A composition comprising liposomes that contain at least one biologically active agent

wherein the ordered bilayer(s) of said liposomes consist(s) essentially of:

(a) one or more vesicle forming lipids, which are phospholipids or sphingolipids such that;

(b) at least 1 mol % of said bilayer(s) is phosphatidylglycerol (PG) and/or phosphatidylinositol (PI);

(c) 5-20 mol % cholesterol; and

wherein said liposomes have a mean diameter between 80-200 nm +/−25 nm; and

have a transition temperature (T c ) of at least 38° C.

which composition is cryostable in the absence of cryoprotectant.