Advances of cyclodextrin polymers for the delivery of biotech drugs

Currently,biological drugs such as gene,protein,and monoclonal antibody are widely applied in the clinic due to their excellent effectiveness.However,they still have some problems,including poor solubility,instability,toxicity,and weak capability to cross cell membranes.Owing to the specific structure of cyclodextrins(CDs)and the advantage of polymeric backbones,various cyclodextrin polymers(CDPs)have been designed as delivery systems for biotech drugs.In this review,after a brief introduction on CDPs and discussion of their physicochemical and biological properties,we will focus on recent advances in the use of CDPs for the delivery of biotech drugs.This review highlights the structure-function relationship of CDPs to their performance in biotech drug delivery.Finally,an outlook will be proposed on the developing trends and challenge in this field.

Advances in cyclodextrin polymers adsorbents for separation and enrichment:Classification,mechanism and applications

Over the past few decades,supramolecular chemistry has entered the field of scientific research and attracted extensive attention.Among supramolecular macrocycles,cyclodextrins(CDs)are widely applied in the field of adsorption due to their unique structure and properties.This review focuses on the important role of cyclodextrin polymers(CDPs)as adsorbents in the adsorption of different substances.It covers the category of CDPs adsorbents(including crosslinked CDPs,grafted CDPs,CD-based polyrotaxanes/pseudopolyrotaxanes,and imprinted CDPs),their adsorption mechanism and applications in the adsorption of inorganic metal ions,organic pollutants,and biomacromolecules.Finally,the challenges and future perspectives in relative research fields are discussed.

Selective removal of phenol by spherical particles of α-,β- and γ-cyclodextrin polymers： kinetics and isothermal equilibrium

Spherical particles of α-,β- and γ-cyclodextrin （CD） polymers to efficiently remove phenol from waste water were prepared by reverse suspension polymerization with epichlorohydrin as crosslinker in liquid paraffin. By controlling the amounts of crosslinker and water, well- defined spherical polymer particles with controllable size were obtained. Due to the selective inclusion associations between CD groups and phenol, these CD spherical polymer particles were demonstrated to be ideal candidates for removal of phenol. Among them β-CD polymer particles showed the best performance. The kinetics and isothermal equilibrium models were used to fit the experimental data of phenol removal from aqueous solution using these CD polymer particles. It was found that the kinetics followed the Ho and Mckay equation, suggesting that the adsorption process of phenol was controlled by diffusion and the host-guest interaction between CD and phenol. Equilibrium isothermal data can be well fitted by the Freundlich equation. The negative free energy change indicated the spontaneous nature of adsorption of phenol by α-,β- and γ-CD spherical polymer particles, while the lowest free energy for β-CD polymer reflected its best adsorption ability, compared to α- and γ- CD polymer particles.

Preparation of insoluble β-CD polymer and its application to enantiomers and isomers separation

An insoluble β-cyclodextrin polymer cross-linked with epichlorohydrin was prepared, and its structure was identified with infrared spectrum. Colloid stationary phase was prepared by dissolving the polymer in the mixed solvent of diisopropyl ether, methylene dichloride and benzene and treated for 0.5 h by ultrasonication, and then was coated on a fused silica capillary column. The optimun reaction conditions are as follows: the mole ratio of epichlohydrin to β-cyclodextrin is 12.1:1, reacting at 65 °C for 24 h. The Chromatographic performance such as column efficiency, thermal stabilities and polarity were studied, two kinds of disubstituted benzene isomers and eight pairs of enantiomers were separated on the capillary column. The results show that the β-cyclodextrin polymer is suitable for use as a capillary gas chromatographic stationary phase, and possess excellent chromatographic properties in separating enantiomers and position isomers.

Study of a water-soluble supramolecular complex of curcumin andβ-cyclodextrin polymer with electrochemical property and potential anti-cancer activity

As a member of the curcuminoid compound family,curcumin(Cur)has many interesting therapeutic properties.However,its low aqueous solubility and stability have resulted in poor bioavailability and restricted clinical efficacy.Based on size matching,β-cyclodextrin polymer(β-CDP),with its hydrophilic polymer chains and hydrophobic cavities,can form an inclusion complex with Cur.To improve the water solubility and stability of Cur,a simple and eco-friendly grinding method was designed to formβ-CDP inclusion complexes.According to the Boltzmann-Hamel's method and Job's method,the molar ratio of theβ-CD unit inβ-CDP to Cur was determined to be 1:1.The diffusion coefficient and diffusion activation energy of Cur-β-CDP were calculated in an electrochemical study.This supramolecular complex worked well in vitro to inhibit the proliferation of hepatoma carcinoma cells HepG2.Remarkably,this method visibly reduced the undesirable side effects on normal cells,without weakening the anti-cancer activity of the drugs.We expect that the obtained host-guest complex will provide a new approach for delivering natural drug molecules,having low water solubility.

Water-soluble crosslinked β-cyclodextrin polymer inclusion complexes with C60

At present, using cyclodextrins or cyclodextrin derivatives with suitable internal annular dimension to embed C60 so as to form inclusion complexes has been one of the main ways to improve C60＇s water-solubility. In three kinds of cyclodextrins (α-, β-, γ-CD), only γ-CD has cavity large enough to include C60 whereas α-, and β-CD have not. In the case of DMβCD, the "out-stretching" methyl groups enlarge the cavity so that it can include C60. Starting from the same thought, we use epichlorohydrin crosslinked