Synthesis Of β-Cyclodextrin-based Drug Carriers And Its Properties

Cyclodextrins (CDs) is a series of cyclic oligosaccharides in general. They are produced from amylose under the action of cyclodextrin glycosyltransferase which is produced by Bacillus. Their structures of the cyclic molecules are made up of the glucose unit bound together by1,4-a-glycosidic linkage. Cyclodextrins have good biocompatibility, and the hydrophobic cavity has the ability to inclusion small molecules. Therefore, new functional materials based on cyclodextrins get increasingly attention. Design and synthesis of cyclodextrin-based precise topology, nanoparticles assembled via host-guest interactions, and specific groups which are stimuli-responsive to the external environment to control drug release, provide new ideas for the field of drug vector synthesis. The powerful functionalization capacity of cyclodextrins makes them attractive to be used as nuclears and synthesize star polymer whose unique topology can be used as excellent precursors for high drug loading carriers.Fullerene has a unique structure and excellent physical and chemical properties, but their hydrophobicity limits its applications in biology, therefore, the design of water-soluble fullerene derivatives and study its biological properties have important significance. The double bond of fullerene can occur the1,3-dipolar cycloaddition, Diels-Alder reaction, etc., which makes fullerene an ideal matrix in drug carrier design. Therefore, covalently attach cyclodextrin to fullerene to increase the water solubility of fullerene and study the in vitro and in vivo properties have important biological significance.In this dissertation, we designed cyclodextrin-containing drug carriers utilizing a variety of chemical synthesis techniques and intermolecular interactions. The main contents are described as below:(1) We present the synthesis of a giant multiarm polymer terminated by β-cyclodextrin (β-CD) and the assembly of this polymer into nanoparticles via the β-CD/adamantane inclusion complex. Ester linkage is introduced to the nanoparticles by design, which enables the nanoparticles to decompose into the multiarm polymers again by hydrolysis of the ester linkage. Thus, this system has the characteristics of MSVs with the nanoparticle as the first stage vector and the giant multiarm polymer as the second stage vector. The multiarm polymer is synthesized by atom transfer radical polymerization (ATRP). Thus, the preparation is facile, and its molecular weight and distribution can be well controlled. The multiarm polymer has abundant hydroxyl groups in the peripheral β-CD moieties which can be used to conjugate drug or other bioactive molecules.(2) We present the synthesis of a novel water soluble C60-CD conjugate containing a hydrophilic spacer of diaminotriethylene glycol. This compound can accumulate in tumor and exhibits an effective DNA cleavage ability under visible light irradiation thanks to the reactive oxygen species generated by the photoexcitation of the C60moiety.(3) A multiarm polymer with β-cyclodextrin as the core, poly (t-butyl acrylate) as arms was synthesized by atom transfer radical polymerization. After hydrolysis, the product of multiarm poly(acrylic acid) was combined with PTX under the catalyst of DMAP/DCC. The results showed that with the increase of polymer molecular weight, the amount of the drug increased, up to59%, and the particles tend to be accumulated in the tumor more easily.