Multivesicular liposomes containing cytarabine for slow-release Sc administration

Sc administration of cytarabine entrapped in multivesicular liposomes to BDF1 mice resulted in slow first-order release from skin, with a half-life of 4 days. The half-life was 10 minutes for unencapsulated free drug. A single-dose sc treatment of BDF1 mice, inoculated iv with 10(5) L1210 leukemia cells 24 hours previously, resulted in long-term survivors over a wide dose range. This study demonstrates that encapsulation of cytarabine in multivesicular liposomes results in slow release from skin and that a single sc dose is often curative for mice with systemic leukemia.