Long-term toxicity of propylene glycol in rats

Abstract

Groups of 30 male and 30 female weanling rats were fed for 2 yr on diets containing 0 (control), 6250, 12,500, 25,000 or 50,000 ppm propylene glycol. The treatments were found to have no effect on mortality, body-weight gain, food consumption, haematology, urinary cell excretion, the urine-concentrating ability of the kidneys, organ weights or pathological findings, including the tumour incidence. In a parallel short-term study in groups of 15 males and 15 females fed 0 or 50,000 ppm propylene glycol in the diet for 15 wk, haematological indices, serum and urine analyses and organ weights were again found to be comparable in the control and test groups. No carcinogenic potential was detected with dietary levels of propylene glycol up to 50,000 ppm, which was also established as the no-untoward-effect level in this study. This level is equivalent to an intake of approximately 2·5 g/kg/day.