Abstract: AIMTo study the pharmaceutical characterization and pharmacokinetics of long-circulating liposomes containing daunorubicin. METHODSThe morphology of daunorubicin long-circulating liposome was surveyed under the transmission electron microscope. The size of daunorubicin long-circulating liposomes was determined by laser scatter method. The entrapment efficiency and accelerative experiment stability of the daunorubicin long-circulating liposomes were examined. Visible spectrophotometry and the HPLC method were established for determination of the daunorubicin in the long-circulating liposomes. The percent release of daunorubicin from long-circulating liposomes in HBS (pH 7.5) and rat serum at 37℃ were examined. The pharmacokinetics in rats were studied. RESULTSThe high entrapment efficiency (>85%) and stabilized long-circulating liposomes could be achieved. The drug was slowly released from the daunorubicin long-circulating liposomes. The drug released from liposomes was less than 10% in 24 h. The T_1/2α and AUC of long-circulating liposome were higher than those in injections. CONCLUSIONThe long-circulating liposomes prepared by us have high encapsulation efficiency and the pharmaceutical characterization showed good stability, they can be used for clinical purpose.