光聚合型pH敏感水凝胶的制备及药物缓释性能

Preparation and Drug Release of UV-Polymerized pH Sensitive Hydrogels

以四臂聚乙二醇(4-arm-PEG,M_n=4000)、ε-己内酯(ε-CL)及丙烯酰氯(AC)为原料合成了大分子单体4-arm-PEG-PCL-AC,在紫外光照射及光引发剂作用下与单体甲基丙烯酸(MAA)共聚交联制备了可生物降解、pH敏感水凝胶。通过红外光谱、核磁共振对大分子单体的结构进行了表征,使用扫描电子显微镜对干胶的微观形态进行观察,并对水凝胶的溶胀、体外降解及药物缓释性能进行了系统的研究。实验结果表明,随着水凝胶中MAA含量的增加及缓冲介质pH值的升高,水凝胶的pH敏感性增强,溶胀率增大;药物释放速率及释放量随pH值的升高而增加;在pH=7.4时,MAA含量越大,水凝胶的药物缓释速率及降解速率越快。该类型的pH敏感水凝胶具有良好的生物相容性、pH敏感性及降解、药物缓释可控性,可应用于药物传送系统,提高水凝胶应用于生物医疗领域时的功能性及疗效。

In this paper, a novel biodegradable pH sensitive hydrogel was prepared by ultraviolet-induced free radical polymerization using 4-arm-poly(ethylene glycol)-poly(ε-caprolactone)-acrylate (4-arm-PEG-PCL-AC) and methacrylic acid (MAA) as crosslinking monomer. The chemical structure of the macromonomer was characterized by IR and 1H-NMR. The morphologies of the dried pH sensitive hydrogels were observed by scanning electron microscope, and the swelling ratio, in vitro degradation and drug release properties of the hydrogels were systematically studied. The results show that the pH sensitivity, equilibrium swelling ratio, drug release rate increase with the increment of medium pH value, and the pH sensitivity and equilibrium swelling ratio also increase with the increment of MAA content in hydrogel. At pH=7.4, the drug release rate and in vitro degradation rate increase with the increment of MAA content. The pH sensitive hydrogels possess a good biocompatibility, pH sensitivity, biodegradability and controlled drug release, which allow it to be used in drug delivery system and improve the application of hydrogels in biomedical field.