| 摘要: |
| 目的：探讨咖啡因在大鼠各肠段的吸收动力学特征。方法：采用大鼠在体小肠回流装置,在浅麻醉状态下,主要从吸收部位、药物浓度、pH值等3方面对咖啡因的肠段吸收特性进行研究。以UV法和HPLC法分别测定酚红和咖啡因的含量。结果：咖啡因在小肠的吸收速率常数（Ka）在药物浓度为2.5、5、102、5 mg/L时分别为0.252、0.247、0.304、0.232 h^-1;在pH值为7.8、6.8、5.4时分别为0.267、0.274、0.247 h^-1;在十二指肠、空肠、回肠和结肠时分别为0.112 0、0.099 6、0.095 5、0.069 5 h^-1。结论：一定范围的药物浓度对咖啡因Ka无影响;在pH7.8-5.4范围内,药物的Ka无显著变化;药物在十二指肠、空肠和回肠的吸收较好,在结肠的吸收较差;咖啡因在肠道的吸收呈一级动力学过程,吸收机制为被动扩散 |
| 关键词: 咖啡因 肠吸收 药代动力学 |
| DOI：10.3724/SP.J.1008.2007.00318 |
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| 基金项目:军队特需药品临床前研究（2006军新034）. |
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| In vivo intestinal absorption kinetics of caffeine in rats |
| ZHANG Xian,ZOU Hao,GAO Shen |
| (Department of Pharmaceutics, School of Pharmacy, Second Military Medical University, Shanghai 200433, China) |
| Abstract: |
| Objective： To investigate the in vivo absorption kinetics of caffeine at different intestine segments in rats. Methods： The rat intestine was cannulated for in situ recirculation. The absorption kinetics of caffeine,including the absorption segments of intestine,drug concentration and p H value,were investigated in all the rats under light anesthesia. Ultraviolet light spectrometry and high-performance liquid chromatography were used to determine the concentrations of phenol red and caffeine, respectively. Results： The absorption rate constants （Ka） of caffeine in the small intestine at the concentrations of 2.5,5,10 and 25 mg· L^-1 were0.252,0.247,0.304 and 0.232 h^-1,respectively. The Ka values at pH of 7.8,6.8,and 5.4 were 0.267, 0. 274 and 0. 247 h^-1 ,respectively. The Ka values in the duodenum,jejunum,ileum,and colon were 0. 112,0. 099,0. 095 and 0. 069 5 h^-1 ,respectively. Conclusion, Concentration and pH value have no obvious effect on the absorption kinetics of caffeine. Caffeine can be better absorbed in the duodenum,jejunum and ileum than in the colon. The absorption of caffeine in the intestine is a first-order process through passive diffusion mechanism.[ |
| Key words: caffeine intestinal absorption pharmacokinetics |
