Propane-1,2-diol

Endpoint summary

Additional information

Genetic toxicity of monopropylene glycol has been studied in a number of in vitro and in vivo assays. Ishidate et al., 1994 reported the results of the Ames test with Salmonella typhimurium strains TA 92, TA 94, TA 98, TA 100, TA 1535, TA 1537 at concentration levels up to 10 mg/plate in the presence of metabolic activation system. No increase in the number of revertants was observed at any dose levels. Also negative results were reported by Pfeiffer et al., 1980, who reported the results of the Ames test with S. typhimurium strains TA 1535, TA 1537, TA 98 and TA 100 at concentration range between 5 and 300 µmol/plate (380-228270 µg/plate) without metabolic activation. Monopropylene glycol also did not induce the increase in chromosome aberration frequency in human embryonic lung culture cells at test levels 0.001, 0.01 and 0.1 µg/ml (Litton Bionetics, Inc., 1974), and in human lymphocytes at dose levels up to 3810 µg/ml, both in the presence and absence of metabolic activation system (Huntingdon Research Center Ltd., 1990).

Also results of several in vivo studies addressing chromosome aberrations were reported. The study of Litton Bionetics, Inc., 1974, reported the results of a micronucleous test with rats and a dominant lethal assay with rats treated with monopropylene glycol. In the first experiment, groups of 5 male rats were administered by gastric intubation either a single dose of monopropylene glycol at dose levels of 30, 2500 and 5000 mg/kg bw (acute study), or 5 times the same doses 24 hours apart (subacute study). In the acute study animals were killed 6, 24 and 48 hours post-administration, in the subacute study 6 hours after the last dose. In the second study, male rats were administered the test substance at the same dose levels by oral gavage either once (acute study), or for 5 days (1 dose/day, subacute study). Following the treatment, the males were sequentially mated to 2 females per week for 8 weeks (7 weeks in subacute study). Females were killed at 14 days after separating from the male, and at necropsy the uterus was examined for early deaths, late fetal deaths and total implantations. In both cases no evidence of genotoxic effect was observed. Also negative results were reported in the mouse micronucleus test by Hayashi et al., 1988, who administered propylene glycol by single intraperitoneal injection at dose levels of 0, 2500, 5000, 10000 and 15000 mg/kg bw to groups of 6 male mice. Animals were killed 18 hr post-administration and femoral bone marrow cells were scored for the number of micronucleated polychromatic erythrocytes. Three of six mice from the top dose group died during the course of the study. There was no statistically significant increase or trend in mononucleated polychromatic erythrocytes numbers. The percentage of polychromated erythrocytes in the top dose group appeared decreased relative to controls (31% versus 54%) suggesting that the test substance had reached the bone marrow.  

There are no in vitro mammalian mutagenicity tests with monopropylene glycol available. However, the study is considered scientifically unjustified, as based on the absence of neoplastic and pre-neoplastic lesions in available chronic studies, the substance is deemed not capable of inducing a genetic damage in vivo. It is also of very low toxicity and readily catabolised via intermediary metabolism, thus entering the pool of endogenous substances. Furthermore monopropylene glycol has been proven not to be mutagenic in bacterial mutation tests, which is a strong indication it does not have the potential to induce changes in DNA base sequences.

Overall, based on the overall evidence, the substance is concluded to be non-genotoxic.

Short description of key information:
Based on the negative results of several Ames tests, in vitro chromosomal aberrations tests and in vivo dominant lethal assay with mice, mouse micronucleous test and chromosome aberration test with rats, monopropylene glycol is considered to be non-genotoxic.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the negative results from the available in vitro and in vivo assays, classification of monopropylene glycol for genetic toxicity is not warranted in accordance with Directive 67/548/EEC and EU Classification, Labeling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.