A toxicological review of the propylene glycols

Tox-Logic Consulting, LLC , Petaluma, CA , USA .
Critical Reviews in Toxicology (Impact Factor: 5.1). 04/2013; 43(4):363-90. DOI: 10.3109/10408444.2013.792328
Source: PubMed


Abstract The toxicological profiles of monopropylene glycol (MPG), dipropylene glycol (DPG), tripropylene glycol (TPG) and polypropylene glycols (PPG; including tetra-rich oligomers) are collectively reviewed, and assessed considering regulatory toxicology endpoints. The review confirms a rich data set for these compounds, covering all of the major toxicological endpoints of interest. The metabolism of these compounds share common pathways, and a consistent profile of toxicity is observed. The common metabolism provides scientific justification for adopting a read-across approach to describing expected hazard potential from data gaps that may exist for specific oligomers. None of the glycols reviewed presented evidence of carcinogenic, mutagenic or reproductive/developmental toxicity potential to humans. The pathologies reported in some animal studies either occurred at doses that exceeded experimental guidelines, or involved mechanisms that are likely irrelevant to human physiology and therefore are not pertinent to the exposures experienced by consumers or workers. At very high chronic doses, MPG causes a transient, slight decrease in hemoglobin in dogs and at somewhat lower doses causes Heinz bodies to form in cats in the absence of any clinical signs of anemia. Some evidence for rare, idiosyncratic skin reactions exists for MPG. However, the larger data set indicates that these compounds have low sensitization potential in animal studies, and therefore are unlikely to represent human allergens. The existing safety evaluations of the FDA, USEPA, NTP and ATSDR for these compounds are consistent and point to the conclusion that the propylene glycols present a very low risk to human health.

Download full-text


Available from: Jeff Fowles, May 20, 2015
34 Reads
  • Toxicology Letters 08/2013; 221:S227-S228. DOI:10.1016/j.toxlet.2013.05.548 · 3.26 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: 2-Hydroxypropylmercapturic acid (2-HPMA) is a urinary biomarker of exposure to propylene oxide, a mutagen and carcinogen to which humans are exposed through inhalation of cigarette smoke as well as in certain environmental and occupational settings. 2-HPMA is the final product of a detoxification pathway in which propylene oxide is conjugated with glutathione, and the resulting conjugate is further metabolized and excreted. We have developed and validated a liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometric (LC-APCI-MS/MS) method for the rapid quantitation of 2-HPMA in human urine. The method was applied to an analysis of urine samples from 40 smokers and 40 nonsmokers as well as from a group of 15 subjects who quit smoking. The results demonstrate that smokers have significantly (P<0.001) higher levels of urinary 2-HPMA (median=480pmol/mg creatinine) than do nonsmokers (208pmol/mg). Similarly, subjects who quit smoking for four weeks exhibited a significant (P<0.001) 52% median decrease in urinary 2-HPMA upon cessation. Approximately 5% of all urine samples had unusually high levels of 2-HPMA (>10 times higher than the median), apparently unrelated to tobacco smoke exposure or available demographic data. The method presented here can be used to rapidly quantify an individual's exposure to propylene oxide via tobacco smoke or other sources.
    Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 02/2014; 953-954C(1):126-131. DOI:10.1016/j.jchromb.2014.02.001 · 2.73 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To review the available evidence evaluating the toxicological profiles of electronic cigarettes (e-cigarettes) in order to understand the potential impact of e-cigarettes on individual users and the public health. Systematic literature searches were conducted between October 2012 and October 2013 using five electronic databases. Search terms such as 'e-cigarettes' and 'electronic delivery devices' were used to identify the toxicology information for e-cigarettes. As of October 2013, the scientific literature contains very limited information regarding the toxicity of e-cigarettes commercially available in the USA. While some preliminary toxicology data suggests that e-cigarette users are exposed to lower levels of toxicants relative to cigarette smokers, the data available is extremely limited at this time. At present, there is insufficient toxicological data available to perform thorough risk assessment analyses for e-cigarettes; few toxicology studies evaluating e-cigarettes have been conducted to date, and standard toxicological testing paradigms have not been developed for comparing disparate types of tobacco products such as e-cigarettes and traditional cigarettes. Overall, the limited toxicology data on e-cigarettes in the public domain is insufficient to allow a thorough toxicological evaluation of this new type of tobacco product. In the future, the acquisition of scientific datasets that are derived from scientifically robust standard testing paradigms, include comprehensive chemical characterisation of the aerosol, provide information on users' toxicant exposure levels, and from studies replicated by independent researchers will improve the scientific community's ability to perform robust toxicological evaluations of e-cigarettes.
    Tobacco control 05/2014; 23 Suppl 2(Suppl 2):ii18-ii22. DOI:10.1136/tobaccocontrol-2013-051474 · 5.93 Impact Factor
Show more