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目的利用聚乙二醇-聚磺胺二甲氧嘧啶(PEG-b-PSD)和PAMAM树状大分子制备具有pH敏感性的复合物胶束并对其制剂学性质进行研究。方法利用正负电荷的相互作用使PEG-b-PSD与PAMAM树状大分子在pH值为7.4条件下形成复合物胶束。考察正负电荷比、离子强度等对zeta电位、载药效果和粒径的影响。利用透射电镜观察制剂形态,考察制剂在不同pH缓冲液和血浆中的释放行为。结果采用正负电荷比为1∶1制备PAMAM/PEG-b-PSD复合物,制剂粒径为50 nm左右,形态为类球形,体外释放速率在pH值为6.5的PBS水溶液中要明显慢于在pH值为7.4的PBS水溶液和血浆中。结论 PEG-b-PSD与PAMAM利用正负电荷相互吸引的方式形成复合物,该复合物具有明显的pH值敏感性,适用于在低pH值部位定位释放药物。
OBJECTIVE: To prepare pH-sensitive complex micelles using polyethylene glycol-poly-sulfamidomethoxine (PEG-b-PSD) and PAMAM dendrimers and to study their formulation properties. The method makes use of the interaction between positive and negative charges to make the PEG-b-PSD and PAMAM dendrimer form complex micelles under the condition of pH 7.4. Investigate the positive and negative charge ratio, ionic strength on zeta potential, drug effect and particle size. The morphology of the preparation was observed by transmission electron microscopy and the release behavior of the preparation in different pH buffers and plasma was investigated. Results The PAMAM / PEG-b-PSD complex was prepared with a positive / negative charge ratio of 1: 1. The particle size of the PAMAM / PEG-b-PSD complex was about 50 nm and its morphology was spheroidal. The release rate in vitro was significantly slower than that of PBS In PBS aqueous solution at pH 7.4 and plasma. Conclusion PEG-b-PSD and PAMAM form a complex with positive and negative charges attracting each other. The complex has obvious pH sensitivity and is suitable for positioning and releasing drugs at low pH.