Propylene glycol is essentially colourless and has a slight odour. Propylene glycol is completely miscible with water and many organic solvents and will dissolve a number of resins, dyes and essential oils. Because of its mutual solvent properties, both aromatic chemicals and essential oils can be dissolved in propylene glycol and then diluted with water. In cosmetic and pharmaceutical formulations, propylene glycol (USP grade) acts as a softening agent, ointment base, preservative, humectant and emollient. Propylene glycol is a component of many cosmetic ingredients. Many grease-like materials can be presented in attractive form through the proper use of this product. Propylene glycol assists in the formation of oil-in-water emulsions. It couples lanolin, oil and soap into water in cold creams and cleansing creams, helps to overcome flaking and rolling in vanishing creams, and generally prolongs the shelf life of most cosmetic formulations. It is also an excellent solvent for dyes and most perfumes, allowing the dispersion of these materials throughout the preparation. Addition of propylene glycol to hand lotions ensures complete and rapid absorption of the protective ingredients by the skin. Propylene glycol is also used in shaving creams to maintain the proper degree of moisture content. Many cosmetic formulations using lemon or other natural fruit juices contain propylene glycol as an inhibitor of mold growth. Storage: Propylene glycol is noncorrosive and nontoxic; it has a low vapor pressure and high flash point. Store in a cool, dry, well-ventilated place.
