Construction Of Drug-loaded Nano Particle Syatems Of Water-soluble Amino Acid Per-substituted Pillar[5]arene And Preliminary Study On Their Antitumor Activity

Nano drug with good biocompatibility,sustained release property and targeting effect were prepared by combining nanotechnology with traditional chemical drugs,which provide new therapeutic strategies for cancer.Supramolecular nano-drug carriers based on noncovalent bond interaction break the limit of traditional covalent chemical building materials.Weak interaction and dynamic reversibility of noncovalent bond endow supramolecular nano-drug carriers with good stimulation performance,which provides good strategies for controlling release of drug.In this thesis,amino acid cations with good biocompatibility and low toxicity were constructed on the pillar[5]arene skeleton,and then a series of pH responsive supramolecular nano carriers were fabricated by host-guest self-assembly strategy,and their drug loading and antitumor activities were studied.（1）Firstly,1,4-dibromo-butylbenzene 1 was prepared from hydroquinone and dibromobutane,followed by one-step reaction with paraformaldehyde using Fe Cl₃as catalyst in dichloromethane to obtain bromobutoxy-subustituted pillar[5]arene derivative 2.Then the nucleophie substitution reaction of intermediate 2 with D-Boc-alanine（L-Boc-alanine）and Boc-phenylalanine provided corresponding Boc-alanine ester pillar[5]arene（D-BAP5 and L-BAP5）and Boc-phenylalanine ester pillar[5]arene（BPAP5）,respectively.The target componds L-alanine ester pillar[5]arene（L-AP5）and D-alanine ester pillar[5]arene（D-AP5）were synthesized by N-Boc group deprotection of BAP5 in 4N HCl/dioxan.The structures of pillar[5]arene derivatives were characterized by ¹HNMR,¹³CNMR,and MALDI-TOF-MS.（2）The complexation behavior of D-AP5 with series of guests SBDS,SDS,and SL in aqueous solution was studied by ¹HNMR and UV.The result shows that the long alkyl chain of the guests can thread into the host cavity,while the terminal sulfonic or carboxyl anions interact with the ammonium cation on D-AP5,indicating that the main driving force of the host-guest complex is CH（?）,electrostatic and hydrophobic interaction.The Job plot curve method was used to determine the complexation modes of the host and three guests,and the formation of[2]pseudorotaxane was carried out in a 1:1complexation mode SDBS@D-AP5,SDS@D-AP5 and SL@D-AP5.And their binding constant were 2.51×10³M^-1,3.63×10³M^-1,and 9.03×10³M^-1,respectively,indicating that the change of the side chain group of the guest has a great influence on the interaction between the host and the guest.（3）Three kinds of supramolecular nano particles SDBS（?）D-AP5,SDS（?）D-AP5 and SL（?）D-AP5 were constructed by host-guest self-assembly and characterized by AFM,TEM and DLS.The results showed that the three nano particles were regular spherical structure with the hydrated particle size of154nm,102nm and 158nm,respectively.After the interaction with anticancer drug cationic doxorubicin（DOX）,their hydrated size increased to 192nm,221nm and 239nm,respectively,indicating the nano particles successfully encapsulated DOX and have good encapsulation efficiency and entrapment efficiency,which were shown as follows:62.6%and 9.36%for SDBS（?）D-AP5;75.1%and 10%for SDS（?）D-AP5 and,60%and 10.5%for SL（?）D-AP5,respectively.The drug release results showed that the three nano drug delivery systems excibited good pH-sensitivity.Their cumulative 12 h drug release rates in deionized water（pH=7.0）and the imitation of tumor weak acid environment（pH=6.2;pH=4.8）are shown as follows:DOX（?）SDBS（?）D-AP5（36.7%at pH=7.0,57.0%at pH=6.2 and 72.2%at pH=4.8）;DOX（?）SDS（?）D-AP5（24.9%at pH=7.0,60.3%at pH=6.2 and 76.7%at pH=4.8）;and DOX（?）SL（?）D-AP5（40.0%at pH=7.0,80.1%at pH=6.2 and 83.3%at pH=4.8）.These results showed that the three supra-molecular nano-drug delivery system are expected to achieve accurate and controlled drug release in cancer treatment.（4）The inhibitory activities of nano carriers（SDBS（?）D-AP5,SDS（?）D-AP5 and SL（?）D-AP5）and their drug delivery systems（DOX（?）SDBS（?）D-AP5,DOX（?）SDS（?）D-AP5 and DOX（?）SL（?）D-AP5）on cervical cancer cells（Hela）,liver cancer cells（Hep G2）,gastric cancer cells（MGC-803）and bladder cancer cells（T24）were tested by MTT method,and the cytotoxicity of these empty three nano carriers to normal cells L-02 was also tested.The results showed that empty nano carriers had low cytotoxicity to normal cells and cancer cells,and the constructed drug delivery systems exhibited good inhibitory activity on the tested tumor cells.Compared with naked DOX,all the nano drug delivery systems had lower IC50 value,suggesting the stronger inhibitory activity（except DOX（?）SL（?）D-AP5 had slightly lower T24 inhibitory activity than DOX）.Moreover,the drug delivery systems can show excellent inhibitory effect on some tumor cells in a short time,especially for Hep G2,the IC50（24h）of DOX（?）SDBS（?）D-AP5,DOX（?）SDS（?）D-AP5 and DOX（?）SL（?）D-AP5 were 0.77（?）M,0.79（?）M and 1.04（?）M,respectively,which were 22%,23%and 30%of that of DOX（3.43（?）M）.The constructed supramolecular drug delivery system has potential application value in the treatment of tumor,which is worthy of further study.