SUBCHRONIC INHALATION AND ORAL TOXICITY OF N-VINYLPYRROLIDONE-2 - STUDIES IN RODENTS

N-Vinylpyrrolidone-2 (NVP) is a monomeric compound used as an industri al intermediate. Nine of 11 studies previously reported involved expos ure of rats (two different strains), mice or hamsters to NVP by the in halation route at concentrations of up to 120 ppm (6 hr/day, 5 days/wk ) over a period of 1 wk to 12 months. The remaining two studies involv ed exposure of rats to NVP through the drinking water or by gavage at dose levels of up to 100 mg/kg body weight/day. Reduced body weight ga in was seen in rats exposed by inhalation to 5 ppm or more for 3 month s and in mice and hamsters exposed to 45 ppm for only 1 day. Effects w ere seen on haematological (reduced haemoglobin, erythrocyte count, ha ematocrit) and clinical chemistry parameters (specially raised gamma-g lutamyltransferase activity and decreases in plasma protein), liver we ight increase and liver lesions (centrilobular single-cell necrosis an d foci of hepatocellular alteration) in rats and mice but not hamsters . Rats exposed to 40 mg/kg body weight/day NVP or more for 3 months by gavage developed similar liver changes. Atrophy of olfactory epitheli um and hyperplasia of nasal respiratory epithelium was seen in rats ex posed by inhalation to 5 ppm NVP for 7 wk but not in response to 1 ppm for 13 wk (no observed-adverse-effect level, NOAEL). These studies in dicated that the upper respiratory tract and the liver are the main ta rgets for NVP toxicity. (C) 1997 Elsevier Science Ltd. All rights rese rved.