Abstract: The stealth liposomal doxorubicin and regular liposomal doxorubicin were prepared with and without polyethylene glycol-distearoylphosphatidylethanolamine (PEG2000-DSPE) by the method of ammonium sulfate gradient, respectively. A reversed HPLC-UV method was established to determine the concentrations of doxorubicin in mice tissues after administration. The tissue distribution of stealth liposomal, regular liposomal and free doxorubicin (doxorubicin hydrochloride solution) in mice and pharmacokinetics were investigated. The results showed that the distribution and pharmacokinetics of stealth liposomal doxorubicin in mice were pronouncedly changed as compared with regular liposomal doxorubicin and free doxorubicin. The levels of liposomal doxorubincin in the heart tissues were reduced and those of in the blood increased, especially of stealth liposomal doxorubicin. In evaluation of antitumor activity, the differences between stealth liposomal doxorubicin and regular liposomal doxorubicin were that the inhibition rate of solid tumor weight for stealth liposomal doxorubicin was higher than that of regular liposomal doxorubicin. It is concluded that the PEG ylation of liposomes can pronouncedly prolong the circulation time of doxorubicin in mice blood and increase the antitumor activity.

Key words: Doxorubicin, Doxorubicin, Liposomes, Liposomes, HPLC-UV, HPLC-UV, Ttissue distribution, Ttissue distribution, Antitumor, Antitumor, Mice, Mice