通过在淀粉分子中引入羧甲基基团，制备了淀粉基胃漂浮控释系统载体材料。系统考察了不同羧甲基取代度对淀粉基胃漂浮控释系统载体结构和性能的影响规律。结果显示，随着取代度的提高，羧甲基淀粉的结晶程度降低，溶胀性能先增大后降低，当取代度为0.08时，其溶胀性能比原淀粉提高了10倍。在此基础上，选择维生素 B1作为模型功能活性物质，羧甲基淀粉作为胃漂浮控释系统载体材料，制备了胃靶向漂浮控释系统，并考察了其对维生素 B1在体外模拟胃液中的释放性能。结果表明，羧甲基淀粉胃漂浮控释系统具有良好的漂浮性能和控缓释性能。以取代度为0.08的羧甲基淀粉为载体，所制得的淀粉基胃漂浮控释系统起漂时间小于2 min，持续漂浮时间可达8 h。体外释放动力学研究显示，此羧甲基淀粉胃漂浮控释系统可使维生素B1释放时间延长至6 h，释放行为符合零级动力学。

Carboxymethyl groups were introduced into starch molecules to obtain a starch-based gastric floating drug carrier. The influence of degree of substitution (DS) of the carboxymethyl group on the structure and performance of the starch-based gastric floating drug carrier was investigated systematically. The results showed that, with increasing DS of the carboxymethyl group and decreasing crystallinity of carboxymethyl starch, the swelling property decreased after the initial increase; when the DS was 0.8, the swelling index of carboxymethyl starch increased by ten times compared with that of the native starch. Based on this result, a gastric floating drug delivery system was prepared with vitamin B1 as a functionally active substance and carboxymethyl starch as the carrier material. The in vitro release behavior of vitamin B1 gastric floating tablets was evaluated in simulated gastric fluid. The results revealed that the carboxymethyl starch based gastric floating tablets had good floating and sustained-release properties. When the carboxymethyl starch with a DS of 0.08 was used as the carrier, the tablets could maintain floating in gastric fluid for 8 h with a floating lag time of less than 2 min. The in vitro drug release kinetics suggest that the carboxymethyl starch based gastric floating system can extend the vitamin B1 release time to 6 h, and the release behavior follows zero order kinetics.

国家自然科学基金项目（31271824）；国家科技支撑计划项目(2012BAD33B04)；高等学校博士学科点专项科研基金(20120172110014)；教育部新世纪优秀人才支持计划项目（NCET-12-0193）