在体单向肠灌流模型研究瑞香素的大鼠肠吸收特性
Intestinal absorption of daphnetin by rats single pass perfusion in situ
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摘要:
考察药物浓度、肠段、pH及P-gp对瑞香素肠吸收的影响。以酚红为标示物, 采用大鼠在体单向肠灌流法研究瑞香素3个剂量组 (10、20和40 μg·mL−1) 在大鼠的十二指肠、空肠、回肠及结肠的吸收情况。实验结果发现瑞香素在pH 6.0时较为稳定, 肠道酶对其代谢影响很小; 瑞香素在低、中、高3个浓度下, 各小肠段的有效渗透系数 (Peff) 有上升趋势, 且高浓度与低浓度相比, 在空肠和结肠的Peff差异显著 (P < 0.05), 由此可推测在实验浓度范围内, 瑞香素在大鼠肠道内的吸收机制可能为被动扩散; 瑞香素在小肠内无特定吸收部位, 但与结肠相比, 小肠有较好吸收, 且存在显著性差异 (P < 0.05); 盐酸维拉帕米的加入对瑞香素4个肠段的吸收均无显著性差异 (P > 0.05), 由此推断瑞香素可能不是P-gp底物。
Abstract:This study investigated the effects of concentration, intestinal section, pH and P-gp on the absorption of daphnetin. The absorptions of three concentrations (10, 20, 40 μg·mL−1) of daphnetin in different intestinal segments were studied with phenol red as the marker by in situ rats single pass perfusion model. The results showed that daphnetin was stable under pH 6.0 condition and little affected by metabolism enzyme. There was upgrade tendency between the Peff of duodenum, jejunum, ileum and colon in different concentration of daphnetin, and it has obvious difference between the high concentration and low concentration in jejunum and colon, which indicated that the absorption of daphnetin was passive diffusion and no difference in different segments of rat intestine. However, compared with colon, the absorption of small intestine was better significantly (P < 0.05). Daphnetin may be not a substrate of P-gp as verapamil had not significantly affected the absorption of daphnetin in different intestinal segments of rats.
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