尼莫地平大鼠在体肠吸收动力学

目的研究尼莫地平在大鼠各肠段的吸收动力学特征。方法采用大鼠在体肠段灌流实验 ,主要从吸收部位、药物浓度、pH值等 3方面对尼莫地平的肠段吸收特性进行研究。结果尼莫地平在大鼠肠道内无特定吸收部位 ,各肠段吸收速率常数按十二指肠、空肠、结肠、回肠顺序依次下降 ,吸收速率常数分别为 0 0 6 87、0 0 6 2 0、0 0 5 97、0 0 4 89h-1。在 4 8～ 14 3μmol·L-1浓度内药物吸收量与浓度呈线性关系 ;在 pH 5 0～ 7 4内药物吸收不受 pH值影响。 结论尼莫地平在大鼠全肠段均有吸收 ,吸收符合一级动力学特征 ,吸收机制为被动扩散 ,适于制备日服 1次缓释给药系统

Study on the absorption kinetics of nimodipine in rat's intestine in situ

Objective To explore the absorption characteristics and mechanism of nimodipine for various intestinal segments.Methods The absorption kinetics and absorption site were investigated using in situ perfusion method in rats.The effects of pH value,absorption site and drug concentration on nimodipine absorption were studied.Results Nimodipine has no specific absorption site in rat′s intestine.The absorption rate constants were 0.068 7, 0.062 0, 0.048 9, 0.059 7 h -1 at duodenum,jejunum,ileum and colon,respectively.Conclusions Nimodipine shows absorption behaviour from the whole intestine.The absorption of the drug conforms to the passive transport mechanism and first-order kinetics.The results indicate that nimodipine can be formulated and prepared as sustained-release dosage form.