An in vitro study of the intestinal absorption of pyridinium aldoximes.

1. The transfer rates of three pyridinium aldoximes, a non-quaternary pyridine aldoxime and choline across the wall of sacs from the jejunum of rats were measured in vitro.2. The transfer rates observed for any one of the quaternary compounds could be inversely correlated with the transmural potential of the particular sac studied, but there was no correlation with the rates of water or glucose transfer.3. 2-hydroxyiminomethyl-N-methylpyridinium iodide (PAM) had a transfer rate seven times less than that of its non-quaternary analogue, 2-hydroxyiminomethyl pyridine.4. Neither neostigmine nor EDTA affected the transfer rate of PAM in the conditions used.5. It was concluded that the transfer of the quaternary compounds could be explained by diffusion through aqueous pores.