东莨菪素大鼠在体胃、小肠吸收动力学研究

Studies on absorption kinetics of scopoletin in rat stomachs and intestines

目的:研究东莨菪素在大鼠胃、小肠的吸收特性。方法:采用大鼠在体胃、小肠吸收实验模型,以高效液相色谱法测定灌注液中药物的浓度,紫外分光光度法测定酚红的浓度。结果:东莨菪素在大鼠胃中2 h的吸收百分率为76.31%;东莨菪素在结肠、十二指肠、回肠、空肠的吸收率分别为46.25%,40.54%,38.21%,32.77%;不同质量浓度东莨菪素(10.014 4,20.028 8,40.057 6 mg.L-1在小肠的吸收速率常数分别为0.643 4,0.613 7,0.597 0h-1;不同pH(6.0,6.8,7.4)在小肠的吸收速率常数分别为0.621 7,0.603 3,0.613 7 h-1。结论:不同质量浓度、pH对东莨菪素在大鼠全肠道的吸收没有显著性影响,药物的吸收呈一级动力学过程,吸收机制主要为被动扩散;东莨菪素在胃肠道均有较好的吸收,结肠为最佳吸收部位,提示适宜制成缓控释制剂。

Objective： To study absorption kinetics of scopoletin in rat stomachs and intestines. Method： Rats was cannulated for in situ recirculation. UV and HPLC methods were used to determine the concentrations of phenolsulfonphthalein and scopoletin, respectively. Result： The absorption rates in rat stomachs at 2 h after administration was 76. 31% ; The absorption rates at colon, duodenum, ileum and jejunum were 46. 25%, 40. 54%, 38.21%, 32.77%, respectively. The absorption rate constant （Ka） at concentrations of 10. 014 4, 20. 028 8-40. 057 6 mg · L^-1 in intestine were 0. 643 4, 0. 613 7, 0. 597 0 h^-1 , respectively. The Ka of seopoletin at pH of 6. 0, 6. 8 and 7.4 in intestine were 0.621 7,0. 603 3,0.613 7 h ^- 1, respectively. Conclusion： The concentrations and pH values of scopoletin solution had no distinctive effect on the absorption kinetics. The absorption of scopoletin was a first-order process with passive diffusion mechanism. Scopoletin was well absorbed at stomachs and intestines in rats. Colon was the best absorption site of scopoletin, which suggest that a sustained-release preparation should be suitable for this compound.