Propanediol, also called propane-1,2-diol, is an organic compound with the chemical formula C3H8O2.
It is produced on a large scale and is primarily used in the production of polymersbut also sees use in food processing as the E-number E1520.
Propylene glycol is used as a humectant (E1520), solvent, and preservative in food and for tobacco products. It is also one of the major ingredients (30-92%), along with vegetable glycerin, of the “e-liquid” and cartridges used in electronic cigarettes(as well as liquid nicotine), where it is vaporized in the atomizer. Propylene glycol is also used in various edible items such as coffee-based drinks, liquid sweeteners, ice cream, whipped dairy products and soda. Vaporizers used for delivery of pharmaceuticals or personal-care products often include propylene glycol among the ingredients. Propylene glycol is used as a solvent in many pharmaceuticals, including oral, injectable and topical formulations, such as for diazepamand lorazepam which are insoluble in water
Propylene glycol has a number of safety issues associated with it. It is commonly known to be an irritant to the skin and eyes, and cause contact dermatitis and rash in humans. However, the Agency for Toxic Substances and Disease Registry disputes the level of toxicity and says “propylene glycol rarely causes toxic effects, and then only under very unusual circumstances.” This is probably due to the fact that propylene glycol is generally used in low concentrations and very few people being sensitive to it at such concentration. Despite this the FDA has it approved for general use under the number E1520 and can be used in cosmetics according to limitations in concentration (Cosmetics Database). This concentration currently stands at <50% according to the Cosmetics Ingredients Review, although research has shown that the body can be sensitive to the ingredient at levels as low as 2%. The Cosmetics Ingredient Review has shown that propylene glycol inhibits collagen contraction. As of yet there has not been enough research conducted to be able to determine whether propylene glycol is carcinogenic (Safety Assessment of Propylene Glycol).
1,3-propanediol is considered to be of low hazard to bodily health by the Cosmetics Database. The National Library of Medicine classifies this ingredient as a skin and eye irritant and study has shown that inhalation of the compound as an aerosol poses no significant risk (Informa Healthcare).
None are recorded.
1,2-propanediol (propylene glycol) and 1,3-propanediol
Source: Wikipedia, https://en.wikipedia.org/wiki/Propylene_glycol