Introduction:
This document provides a comprehensive review of the toxicity of propylene glycol, a chemical commonly used in various industrial and consumer products. The text includes information on the chemical's physical and chemical properties, human and animal exposure, toxicokinetics, toxicity, and carcinogenicity. The reader will learn about the potential health risks associated with exposure to propylene glycol and the regulatory considerations for its use.
Key Points:
* Propylene glycol is a colorless, odorless, and viscous liquid used in various applications, including food, pharmaceuticals, and cosmetics.
* human exposure to propylene glycol is primarily through oral ingestion, with minimal inhalation or dermal exposure.
* The major elimination pathway for propylene glycol in most mammals is via glucuronidation in the liver and subsequent elimination in the urine.
* hematological changes are the critical effect of propylene glycol exposure in animals, but the lack of overt hemolysis and anemia suggests that these effects are minimally adverse.
* There is no evidence that propylene glycol is carcinogenic in rats and dogs based on histological examinations in chronic oral toxicity studies.
* Propylene glycol has been classified as "not likely to be carcinogenic to humans" by the U.S. EPa.
* The subchronic and chronic oral RfD values for propylene glycol are 20 mg/kg-day, based on a NOaEL of 5200 mg/kg-day for reduced RBC counts and hyperglycemia in rats.
* a provisional inhalation RfC for propylene glycol cannot be derived due to the mode of exposure not being relevant for any anticipated human exposure scenario.
Main Message:
The text provides a thorough review of the toxicity of propylene glycol and its potential health risks. The lack of evidence for carcinogenicity and the derivation of oral RfD values suggest that exposure to propylene glycol within acceptable limits is unlikely to pose a significant health risk. however, the potential for hematological effects in animals suggests that further research is necessary to fully understand the potential toxicity of this chemical. The text also highlights the importance of considering the mode of exposure when evaluating the potential health risks associated with chemical substances.
