Metabolism studies of N,N-dimethylformamide

Summary

In a acute inhalation test, 4 persons were subjected to an N,N-dimethylformamide concentration of approx. 26 or 87 ppm. 4 further persons were exposed daily to a concentration of approx. 21 ppm 4 hrs daily on 5 consecutive days. p ]The behaviour of N,N-dimethylformamide and its metabolites (N-methylformamide and formamide) in blood and urine was examined.

N,N-dimethylformamide was no longer detectable in the blood a few hours after inhalation. Only after acute exposure to 87 ppm was it detectable in the urine. The N-methylformamide levels in the blood and liver showed a continuous increase or remained, over a period of some hours, at the same level that recorded immediately after inhalation.

N-methylformamide was detectable in the urine 4 hrs after beginning the exposure. The majority of the substance was eliminated within 24 hrs. The elimination of formamide was delayed.

After repeated exposure to the maximal allowable concentration in the working area (MAC), N-methylformamide did not accumulate in the blood or urine.

The determination of N-methylformamide in the 24-hr urine was suggested as a routine control for employees exposed to N,N-dimethylformamide. Concentration above 50 mg/24-hr urine indicate exposures exceeding the MAC of 20 ppm.