To enhance the accumulation in the tumor and intracellular delivery of the encapsulated doxorubicin(DOX), a pHsensitive doxorubicin nanoliposomes(DOXNL) modified with carboxymethyl chitosan(CMCT) was prepared by thinfilm pH gradient. The nanoliposomes modified with CMCT showed good shape with an average particle size of
(38±221) nm and the drug encapsulation efficiency was about 8883%. The drug release of the CMCTmodified DOX nanoliposomes
in vitro showed obvious pH sensitivity. The Hela cells treated with CMCTDOXNL showed remarkable increase in cellular association or DOX uptake compared with DOXNL. The cytotoxicity of CMCTDOXNL on Hela cells was higher than that of DOXNL. The pHsensitive CMCTmodified DOX nanoliposomes promoted the delivery of the encapsulated DOX into the tumor cells.