Propylene glycol (inci)

Propylene glycol, also known as 1,2-propanediol, belongs to the polyvalent alkanols. Propylene glycol is a chiral racemate and is produced by hydrolysis from propylene oxide. Besides 1,2-propanediol it also contains dipropylene glycol and other polypropylene glycols. Propylene glycol impresses as a syrup-like, odourless, sweet-tasting, strongly hygroscopic liquid. The mixture of substances is miscible with water, ethanol, chloroform and essential oils.

Propylene glycol is widely used pharmaceutically, cosmetically and technically.

Cosmetics: Propylene glycol acts as a moisturizer (increases the water content of the skin) and as a solvent.

Pharmaceutical applications include oral solutions, syrups, injection solutions, essential oils and liquid flavours. Thus, the substance can lead to an improvement in the absorption of various active ingredients. Propylene glycol has an antimicrobial and thus preservative effect in concentrations > 10%. Due to this property, the use of further preservatives can often be avoided.

In food technology propylene glycol is used under the number E 1520.

Propylene glycol is used industrially as a plasticizer, in aerosols for room disinfection, in antifreeze, etc.

Toxicologically propylene glycol is harmless. The substance is well tolerated. An irritation potential of the skin has to be considered depending on the concentration. Additives in external agents of 10 to 15 % are considered to be well tolerable. No appreciable absorption via the skin is to be expected. Propylene glycol is also used as a well-tolerated substance in ophthalmic exteriors.

Ammon H et al (2014). Hunnius Pharmaceutical Dictionary. Walter de Gruyter GmbH Berlin/Boston S 1464-1465