Kasama T, Mayuzumi K, Nakai M, Ohshiro K, Sakaguchi Y, Minohara K, Minato M, Hiura M
J Pharmacobiodyn. 1986 Feb;9(2):139-45. doi: 10.1248/bpb1978.9.139.
An in situ experimental model of rectal absorption was studied in rabbits compared with in vivo determination of drug concentration in the plasma of postcaval vein using indomethacin as drug. Pharmacokinetic parameters were similar between in vivo and in situ. When results from both studies were compared, 60% of the drug administered to the rectum was absorbed from the superior hemorrhoidal vein and the remaining 40% was absorbed from the inferior hemorrhoidal vein. When an aspirin suppository was used in this model, the amount of unaltered aspirin absorbed in the rectal mucosa or space was greater than the absorbed salicylic acid which was metabolized or degradated from aspirin. In the case of insulin, these differences were not seen in the insulin concentration of venous plasma between insulin physiological saline and surfactant suspension. However, using the in situ model, the surfactant effect on rectal absorption of insulin was observed. From the above results, it was concluded that this in situ experimental model of rectal absorption has advantages in that it can be used directly to measure the rectal absorption rate and to determine ratios of easily metabolized and poorly absorbed drugs. Therefore, this model appears to be useful in evaluation of rectal absorption.
以吲哚美辛为药物，在兔体内研究了直肠吸收的原位实验模型，并与通过测定下腔静脉血浆中药物浓度的体内实验进行了比较。体内和原位实验的药代动力学参数相似。当比较两项研究的结果时，直肠给药的药物中60% 是从痔上静脉吸收的，其余40% 是从痔下静脉吸收的。在此模型中使用阿司匹林栓剂时，直肠黏膜或腔隙中吸收的未改变的阿司匹林量大于从阿司匹林代谢或降解而来的吸收的水杨酸量。对于胰岛素，在胰岛素生理盐水和表面活性剂混悬液之间，静脉血浆中的胰岛素浓度未观察到这些差异。然而，使用原位模型，观察到了表面活性剂对胰岛素直肠吸收的影响。从上述结果得出结论，这种直肠吸收原位实验模型的优点在于，它可直接用于测量直肠吸收速率，并确定易代谢和吸收差的药物的比例。因此，该模型似乎可用于评估直肠吸收。
