Lipids and Lipid Compositions for the Delivery of Active Agents

A compound, or salt thereof, of formula (I):

• n is 0, 1, 2, 3 or 4;
• p is 0, 1, 2, 3, 4, 5, 6, 7 or 8;
• L1 is —O— or a bond;
• L2 is —OC(O)— or —C(O)O—;
• R1 is selected from:
• v is 0, 1, 2, 3 or 4;
• w is 0, 1, 2, or 3;
• Cyl is 5-7 membered nitrogen containing heterocycle optionally substituted with one or two alkyl groups;
• Ar is an aryl group, optionally substituted with C1-8 alkyl amino group;
• R and R′ are each, independently, hydrogen or C1-8 alkyl;
• and
• R2 is selected from C6-20 alkyl optionally substituted with a hydroxyl, C15-19 alkenyl, C1-12alkyl-OC(O)—C5-20alkyl, C1-12alkyl-C(O)O—C5-20alkyl and
• R3 is selected from:
• C4-22 alkyl, C12-22 alkenyl,