Baclofen: intestinal absorption mechanism in mice.

1. The duodenal transfer of baclofen from sacs of mouse intestine was determined. 2. A linear relationship between the steady-state transfer rate of total and the initial mucosal baclofen concentration was observed, suggesting that the clearance is the same at different concentrations. 3. There was no significant difference in the amount of total drug removed between control and everted tissues. 4. The data support the idea that the principal transfer mechanism for baclofen is simple diffusion in mouse intestine.