Arimori K, Nakano M
J Pharmacobiodyn. 1985 Apr;8(4):324-7. doi: 10.1248/bpb1978.8.324.
The exsorption of theophylline into the small intestinal lumen after intravenous administration of aminophylline was studied by in situ single-pass perfusion technique. As the concentrations of the drug in the serum and the bile juice were decreased, the exsorption rate of the drug into the perfusate decreased obeying the apparent first-order kinetics. The half-lives of the drug concentrations in the serum and the bile juice were 2.13 and 2.58 h for pH 6.0 isotonic phosphate buffer, and were 2.71 and 2.32 h for pH 8.0 isotonic phosphate buffer, respectively. The amounts of theophylline excreted in the perfusate and the bile juice were 12.08% and 0.17% of dose for pH 6.0 isotonic phosphate buffer, and were 13.81% and 0.20% of dose for pH 8.0 isotonic phosphate buffer. These results demonstrated that a considerable amount of theophylline was exsorbed into the intestinal lumen. The mechanism by which oral activated charcoal enhanced clearance of theophylline administered intravenously may be adsorption of the drug transported into the gastrointestinal tract by the charcoal.
采用原位单通道灌注技术研究了静脉注射氨茶碱后茶碱向小肠肠腔的外排情况。随着血清和胆汁中药物浓度的降低，药物向灌注液中的外排速率降低，符合表观一级动力学。对于pH 6.0的等渗磷酸盐缓冲液，血清和胆汁中药物浓度的半衰期分别为2.13小时和2.58小时；对于pH 8.0的等渗磷酸盐缓冲液，血清和胆汁中药物浓度的半衰期分别为2.71小时和2.32小时。对于pH 6.0的等渗磷酸盐缓冲液，灌注液和胆汁中排出的茶碱量分别为剂量的12.08%和0.17%；对于pH 8.0的等渗磷酸盐缓冲液，灌注液和胆汁中排出的茶碱量分别为剂量的13.81%和0.20%。这些结果表明，相当数量的茶碱被外排到肠腔中。口服活性炭增强静脉注射茶碱清除率的机制可能是活性炭吸附转运到胃肠道的药物。
