Preparation Of Folate-Targeted Liposomes Encapuslating Doxorubicin And Verapamil And Investigation Of In Vitro Cytotoxicity

Objective: According to the DDS theory, conjugating PEG and folate acid and synthesizing complex liposomes targeting folate receptor. Investigating the drug targeting delivery function of TDDS and the role of complex liposomes in reversing MDR in vitro.Method: The topic was based on the above-mentioned idea, selecting commonly clinical antitumor drug doxorubicin and verapamil as model drug. We used folate-targeted liposomes as drug vehicle and selected high folate-expressed resistant cell line MCF-7/DOX as model cell. We carried out MTT experiment to investigate the targeting and MDR reversing effect of the liposomes.Result:In this article,we synthesized membrane material FA-PEG-DSPE , which had high purity and had been identified by TLC.In this thesis, FLDV liposome were prepared by (NH4)2SO4 -gradient method. Firstly, we prepared FLD, and then entraped VER. Through orthogonal experimental design, one optimum recipes of FLD was founded that showed: drug-lipids ratio:1:20, (NH4)2SO4 concentration: 250 mmol/L, incubation temperature:60℃, incubation time 30min, the best condition for encapsulating VER:optimum pH:8.5,drug-lipids ratio:1:40, incubation temperature:60℃, incubation time: 30min. Under the optimal formulation, DOX was encapsulated 92.1%, VER was encapsulated 70.2%.In this thesis , we measured the content and encapsulation efficiency of VER and DOX in liposome by HPLC.The result showed that this method was accurate, sensitive, specific and good enough to be used in pharmacokinetic study of FLD.The liposome observed through transmission electron microscopy presents distribution of size uniformity, the average diameter is about 80nm. The liposomes were filled with nitrogen at 4～25℃for a month,and the stability were investigated by the index of appearance,encapuslation efficiency,TLC spot. The experiment showed that there is no significant index change when the liposomes were stored at 4℃, indicated that the liposomes are stable under this condition, The drug releasing experiment in vitro showed that complex liposomes had more delayed release effect than free drug.The results of liposome MTT experiment suggested IC50 FLDV