Propylene glycol
Propylene glycol is a clear, colorless and hygroscopic liquid. Forty-five percent of propylene glycol produced is used as chemical feedstock for the production of unsaturated polyester resins. Propylene glycol is used as a humectant (E1520), solvent,and preservative in food and for tobacco products. 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 diazepam and lorazepam which are insoluble in water. Propylene glycol is used in veterinary medicine as an oral treatment for hyperketonaemia in ruminants.