【摘要】 目的:研究氧氟沙星在肠道各区段的吸收动力学特征、吸收部位及吸收机制,对氧氟沙星缓释制剂的设计提供重要依据。方法:采用大鼠在体循环方法研究氧氟沙星的肠吸收。结果:在2.0～10.0mg·L-1浓度范围内吸收量与浓度呈线性关系,无高浓度饱和现象,Ka值基本保持不变;在pH5.5～7.4范围内吸收受pH影响;各肠段的吸收速度常数差异有显著性,十二指肠、空肠、回肠的吸收速率常数分别为0.054h-1,0.037h-1,0.0032h-1,在结肠几乎末检测到吸收。结论:氧氟沙星吸收机制为被动转运,在小肠内的吸收呈现吸收一级动力学特征。最佳吸收部位在十二指肠和空肠。更多还原

【Abstract】 OBJECTIVE To explore the absorption properties of ofloxacin from various intestinal segments in order to devise the sustained-release dosage forms of ofloxacin.METHODS In this study,in situ perfusion method were used to study the absorption kinetics of ofloxacin in rats.RESULTS When the concentration was raised from 200 to 1 000 mg·L~-1, the uptake of ofloxacin increased and no saturation phenomenon occurred, whereas the absorption rate constant kept at a same level. The absorption of ofloxacin was influenced by pH value between pH 5.5 and pH 7.4.There were significant differences among the absorption rate constants in different intestinal segments. The absorption rate constants (h~-1) of duodenum,jejunum and ileum per 10 cm were 0.054 4 h~-1,0.036 8 h~-1,0.003 2 h~-1, respectively. The absorption in colon was almost not detected.CONCLUSION The results indicated that absorption of ofloxacin by intestine is mainly via passive transport mechanism and complied with first order kinetics.The best absorption sites of ofloxacin were duodenum and jejunum.更多还原