Toxicity of N-Methyl-2-pyrrolidone (NMP): Teratogenic, Subchronic, and Two-Year Inhalation Studies

Toxicity of N-Methyl-2-pyrrolidone (NMP): Teratogenic, Subchronic,and Two-Year Inhalation Studies. LEE, K. P., CHROMEY, N. C.,CULIK, R., BARNES, J. R., AND SCHNEIDER, P. W. (1987). Fundam.Appl Toxicol. 9,222–235. Pregnant rats were exposed toN-methyl-2-pyrrolidone (NMP) at atmospheric concentrations of0.1 and 0.36 mg/liter for 6 hr/day on Days 6 through 15 of gestation.Except for sporadic lethargy and irregular respiration in severalrats the first 3 days of exposure, there were neither abnormalclinical signs nor pathological lesions in the maternal rats.Exposure did not affect either the outcome of pregnancy or embryonalgrowth rate. No abnormal development was detected in the vitalorgans and skeletons of the fetuses. Rats were exposed to anaerosol-vapor mixture of NMP at concentrations of 0,0.1, 0.5,and 1.0 mg/liter for 6 hr/day, 5 days/week for 4 weeks. At 0.1and 0.5 mg/liter exposure levels, rats did not show any significantclinical signs or pathological lesions. However, lethargy, respiratorydifficulty, and excessive mortality were found in rats exposedto 1.0 mg/liter. These rats had focal pneumonia, bone marrowhypoplasia, and atrophy of lymphoid tissue in the spleen andthymus. These lesions were reversible in surviving rats following2 weeks of recovery. Increases in the relative and absolutenumbers of neutrophils were observed during exposure at 1.0mg/ liter, but returned to normal limits after 2 weeks of recovery.Rats were exposed to vapor of NMP at concentrations of 0, 0.04,or 0.4 mg/liter for 6 hr/day, 5 days/week for 2 years. Malerats at 0.4 mg/liter showed slightly reduced mean body weight.No life-shortening toxic or carci nogenic effects were observedin rats exposed for 2 years to 0.04 or 0.4 mg/liter of NMP.