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目的研究盐酸罗沙替丁醋酸酯(ROX)在大鼠肠的吸收动力学特征。方法采用大鼠在体肠循环法,以双波长紫外-可见分光光度法测定灌流液中ROX浓度,考察不同浓度及不同肠段下ROX的吸收情况并测定吸收动力学参数。结果在不同药物浓度下,ROX小肠吸收速率常数间差异无统计学意义。在肠道各部位的吸收速率按十二指肠、空肠、回肠、结肠顺序下降,吸收速率常数分别为(3.87±0.12)×10~(-2),(2.53±0.18)×10~(-2),(1.43±0.10)×10-2,(0.91±0.15)×10~(-2)·h~(-1)。结论 ROX大鼠在体肠道吸收符合表观一级动力学过程,吸收以被动扩散为主,在整个肠段均有一定的吸收。
Objective To study the absorption kinetics of roxatidine hydrochloride acetate (ROX) in rat intestine. Methods ROX concentration in perfusate was determined by dual-wavelength UV-Vis spectrophotometry in rat intestine circulation method. The absorption of ROX in different concentrations and different bowel segments was investigated and the absorption kinetic parameters were determined. Results There was no significant difference in the rate constant of ROX intestinal absorption under different drug concentrations. The rate of absorption in various parts of the intestine decreased in order of duodenum, jejunum, ileum and colon. The absorption rate constants were (3.87 ± 0.12) × 10 ~ (-2) and (2.53 ± 0.18) × 10 ~ (- 2, (1.43 ± 0.10) × 10-2, (0.91 ± 0.15) × 10 ~ (-2) · h ~ (-1) respectively. Conclusions ROX absorption in the intestine of the rats is consistent with the apparent first-order kinetics. The absorption is dominated by passive diffusion and has some absorption throughout the intestinal segment.