A comparison of the effects of hyperosmotic salicylate solutions in closed and perfused rectal in-situ loops of rats.

The effects of presentation of hyperosmotic solutions of sodium salicylate to the closed and perfused rectal loop preparations commonly used in assessing drug absorption have been compared. Epithelial cell loss was quantified in control and treated loops. Tissue damage was significantly greater (P less than 0.01) in treated perfused loops. Fluid efflux, which was associated with a small but significant change in the haematocrit value, was noted in both systems.