Abstract: AimTo study on the release profile in vitro and biodistribution in mice of the compound liposomes carried with vincristine sulfate (VCR) and mitoxantrone chlorhydric acid (MTO). Methods The release behaviors of the VCR and MTO from compound liposomes were studied in vitro. HPLC was developed for the determination of the contents of VCR and MTO in tissues in mice. ResultsThe release time of VCR from compound liposome was 24 h and that from free drug (in control solution) was 6 h. The release of MTO from compound liposome was 0.05% after 288 h and release time of MTO from free drug (in control solution) was 12 h. The liposomes and free drugs were injected intravenously at same dose to mice. The elimination half-life time (T_1/2) in plasma of liposomal and free VCR were 0.16 h and 0.14 h, and the AUCs (0-48 h) of them were 2.69 (ug·g^-1)·h and 1.58 (ug·g^-1)·h, respectively. The elimination half-life times (T_1/2) in plasma of liposomal and free MTO were 21.6 h and 0.05 h and the AUCs (0-48 h) of them were 17.06 (ug·g^-1)·h and 0.42 (ug·g^-1)·h, respectively. ConclusionThe compound liposome with high entrapping efficiency and small particle size could be prepared by pH-gradients method and reverse evaporation technique. Two drugs were sustained-released from the compound liposome. Mice tail intravenous injection of compound liposomes showed that compound liposome prolonged the retention time and improved the concentration of MTO and VCR in the blood circulation system compared to control. In the mean time, compound liposome reduced the concentration of the MTO and VCR in heart, lung, kidney etc. These observations indicated that compound liposome could improve anticancer activity and reduce side effect.