Controlled Loading And Releasing Of Drug By β-cyclodextrin Polymeric Network

Cyclodextrin hydrogel combines the characteristics of cyclodextrin and hydrogel. It can improve the solubility of hydrophobic drugs, control drug release rate and has good biocompatibility. Using it as a drug carrier has got attention from many researchers.In this work, high solubility polymer β-CD-P was synthesized by crosslinking cyclodextrin with epichlorohydrin, and C18PAA was synthesized through C18grafting to polyacrylic acid chain. These two polymers were characterized by1H NMR, FT-IR and colorimetric method.The inclusion associations between β-CD (or β-CD-P) and drug molecules were studied by UV-vis method. The results show that the β-CD (or β-CD-P) and drug molecules form1:1inclusion complexes, β-CD-P retained the original cavity structure of cyclodextrin. The inclusion constants of β-CD/MLX, β-CD-P/MLX, β-CD/BZ and β-CD-P/BZ were255M-1,1626M-1,1968M-1and2020M-1, respectively. For MLX, the aggregation effect of β-CD-P was more than its steric effect. But for BZ, the aggregation effect of β-CD-P and its steric effect were nearly equal.The β-CD-P/C18PAA polymer networks were prepared based on the inclusion associations between C18and β-CD grafts. Rheological method was used to study the aspects which can affect the viscosity of the polymer networks, such as molar ratio, polymer concentration. Using this polymer network to include drug, can improve the drug solubility in water. For MLX, drug release rate is fast, the gel didn’t have the expected sustained-release effect. But for BZ, can not only achieve a slower release rate, but also control the drug release rate by adjusting the polymer concentration. In addition, drug BZ release properties of β-CD-P/C18PAA and pure C18PAA hydrogel with the same viscosity were studied. Compared to pure C18PAA hydrogel, β-CD-P/C18PAA showed relatively slow release rate, so β-CD-P/C18PAA hydrogels can be used as an ideal drug carrier of BZ.