摘要
采用膜乳化-凝胶化法制备了粒径窄分布的海藻酸钙微球.用不同浓度的氯化钠溶液处理微球来调控微球中的自由羧酸根的含量.用原子吸收光谱和红外光谱表征了微球中钙、钠离子以及化学基团的变化,证明盐处理后海藻酸钙微球内发生了钠离子置换钙离子的过程,海藻酸中的羧酸根由螯合态转变为自由态.用盐处理后的微球吸附带正电荷的小分子抗癌药物阿霉素的能力大大提高,其中用浓度1.8%的氯化钠溶液处理后的微球载药量达到1310μg/mg,是未处理微球的10倍.负载药物的微球具有pH敏感的释放行为,在pH5.5的PBS溶液中的释放速率和释放量显著大于在pH 7.4的PBS溶液中.
Narrow-dispersed calcium alginate microspheres were prepared by a membrane emulsification- gelation method. The microspheres were treated with NaC1 solutions of different concentrations to control the amount of free carboxylate groups. The size of the microspheres increased simultaneously after salt treatment. The quantity of calcium and sodium ions in the microspheres was measured by atomic absorption spectrometer, and the change of functional groups was determined by Fourier transform infrared spectroscopy. During the treatment process calcium ions in the microspheres were replaced by sodium ions, and the carboxylate groups were converted from a chelate to a free state. As doxorubicin hydrochloride was positive in water while alginate was negative,doxorubicin was loaded into the alginate microspheres via electrostatic interaction. The loading capacity of microspheres was enhanced greatly after treatment with NaC1 solution. When the microspheres were treated with 1.8% NaC1 solution,the drug content increased remarkably to 1310 μg/mg,which was nearly 10 times the amount of the untreated ones. In vitro release tests confirmed that relative smaller percentage of drug was released from the microspheres containing more drug. The release behavior of the drug-loaded microspheres was pH-sensitive,i, e. slower at pH 7.4 but faster at pH 5.5. After salt treatment,the drug release mechanism was transformed from diffusion alone to the combination of diffusion and matrix erosion.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2012年第7期771-777,共7页
Acta Polymerica Sinica
基金
浙江省自然科学基金(基金号Z4090177
Y4110064)
科技部中印国际合作项目(项目号2010DFA51510)资助
关键词
膜乳化
海藻酸钙微球
盐处理
阿霉素
药物释放
Membrane emulsification, Alginate microsphere, Salt treatment, Doxorubicin, Drug release
