3.28 : 薬物吸収を研究する方法：イン・サイチュ（in situ）

In situ drug absorption methods mimic in vivo conditions by perfusing a drug solution through an anesthetized rat's intestinal segment.

It includes two key methods: doluisio and single-pass perfusion.

The doluisio method involves connecting the upper and lower parts of a rat's small intestine via tubing and syringes.

Initially, the intestinal segment is washed with normal saline, followed by perfusion with a radiolabelled drug and a non-absorbable marker to indicate water reabsorption.

After passing through the intestinal segment, the drug content collected in the second syringe is measured to determine its absorption. 

In the single-pass perfusion method, the upper part of the rat's intestine is connected to a syringe, and the lower part connects to a separate collection bottle. The drug solution is perfused through the intestinal segment once at a constant rate.

The drug content in the perfusate collected at regular intervals is analyzed to evaluate absorption.