| abstract |
The invention features an improved lipid formulation comprising a cationic lipid of formula (A), a neutral lipid, a sterol and a PEG or PEG-modified lipid, where R 1 and R 2 are independently alkyl, alkenyl or alkynyl, each can be optionally substituted, and R 3 and R 4 are independently lower alkyl or R 3 and R 4 can be taken together to form an optionally substituted heterocyclic ring. In one embodiment, R 1 and R 2 are independently selected from oleoyl, pamitoyl, steroyl, linoleyl and R 3 and R 4 are methyl. Also disclosed are targeting lipids, and specific lipid formulations comprising such targeting lipids. |