Human studies on the bioavailability of a quaternary ammonium compounds, tiemonium iodide and tiemonium methosulphate

Five volunteers were administered capsules containing 14C-labelled tiemonium iodide and 4 volunteers received capsules of 14C-labelled tiemonium methosulphate. Serum, urine and faecal levels of tiemonium were measured. The percentage of the dose absorbed was determined after a further labelled intravenous injection into 3 of the volunteers. The drug appeared to be poorly absorved, as expected for quaternary ammonium compounds, but there was no difference in the bioavailability of these two tiemonium salts.