Patent ID: 8852472

Claim:
A lipid composition comprising: a cationic lipid component that is a compound according to formula (I), wherein R 1 and R 2 are each independently alkyl; n is 1-4; R 3 is acyl selected from the group consisting of lysyl, ornithyl, 2,4-diaminobutyryl, histidyl and an acyl moiety according to formula (II), wherein m is any integer from 1 to 3, wherein the NH 3 + is optionally absent, and Y − is a pharmaceutically acceptable anion, a first helper lipid selected from a phospholipid or a steroid, and a shielding compound comprising PEG, HEG, polyhydroxyethyl starch (polyHES) or polypropylene, wherein said shielding compound provides for a prolonged circulation time in vivo of said lipid composition.