温度和pH双敏性PVME／CMCS水凝胶辐射交联制备及其性能

Preparation of Temperature-and pH-Sensitive PVME/CMCS Hydrogels via Electron Beam Irradiation Cross-linking and Their Properties

以聚甲基乙烯基醚（PVME）和羧甲基壳聚糖（CMCS）为原料，采用电子束辐照交联方法制备聚甲基乙烯基醚／羧甲基壳聚糖（PVME／CMCS）水凝胶，研究了温度、pH值、CMCS含量等对PVME／CMCS水凝胶溶胀度的影响，同时以5-氟尿嘧啶（5-Fu）作模型药物，初步探讨了凝胶药物释放性能．结果表明，辐射剂量在20～40kGy时，凝胶分数随辐射剂量的增加而快速增加，辐射40kGy以后趋于平衡．在相同辐射剂量下，随着体系中CMCS含量的增加，凝胶分数反而减少．该水凝胶具有一定的温度和pH敏感性，其低临界溶解温度（LCST）在35℃左右，并且在相同时间内和25及37℃下的溶胀反复可逆，表现出较快的响应性．pH〈3．0和pH〉5．0时，溶胀度较大；pH值为3．0～5．0时，凝胶网络由于静电力收缩，溶胀度较小．CMCS含量的增加和辐射剂量的减小均可提高凝胶载药量．药物释放时间可通过改变体系中CMCS的含量和辐射剂量来调节．

Hydrogels based on poly（ vinyl methyl ether） （PVME） and carboxymethylchitosan （CMCS） were prepared with electron beam irradiation（EB） cross-linking at room temperature. The effects of temperature, pH, CMCS content on the swelling properties of PVME/CMCS hydrogels were studied. The release behavior of a drug was tentatively investigated as well. The results show that the gel fraction of PVME/CMCS blend gels increases rapidly and then levels off above the radiation dose of 40 kGy, and it decreases with the increase of CMCS content in PVME/CMCS system. The hydrogels are thermo- and pH-sensitive, and show a fast swelling reversibility. At pH 〈 3.0 and pH 〉 5.0, the hydrogels have a higher swelling ratio ; however, the swelling ratio is relatively lower in the pH range of 3.0-5.0 due to the electrostatic force. Increasing CMCS content and decreasing irradiation dose can improve the drug loading. The release of 5-fluorouracil can be governed by regulating the CMCS content and irradiation dose.