Patent ID: 7531676

Claim:
A lipid which has the formula (1): [R 1 ] m (L 1 ) n -[—C(R 2 )(R 3 )(R 4 )] (1) wherein R 1 is a hydrocarbon chain optionally substituted by one or more hydrophilic hydrocarbons each containing two or more atoms or groups capable of being solvated by water, provided that at least one hydrocarbon chain is substituted by at least one hydrophilic hydrocarbon and each hydrophilic hydrocarbon is attached to the hydrocarbon chain to achieve at least a ten atom spacing along the chain between the hydrophilic hydrocarbon and the group -(L 1 ) n -[—C(R 2 )(R 3 )(R 4 ); m is an integer from 1 to 6; L 1 is a linker atom or group; n is zero or the integer 1; —[—C(R 2 )(R 3 )(R 4 )] is a cationic head in which R 2 is a hydrogen atom or an optionally substituted aliphatic, cycloaliphatic, heteroaliphatic, hetero-cycloaliphatic, aromatic or heteroaromatic group optionally containing one or more cationic centres, and R 3 and R 4 which may be the same or different is each an optionally substituted aliphatic, cycloaliphatic, heteroaliphatic, heterocycloaliphatic, aromatic or heteroaromatic group containing one or more cationic centres, or R 3 and R 4 together with the carbon atom to which they are attached form a cycloaliphatic, heterocycloaliphatic, aromatic or heteroaromatic group containing two or more cationic centres; and the salts, solvates and hydrates thereof.