Propylene carbonate

• USP–NFPropylene Carbonate

carbonic acid, cyclic propylene ester; cyclic propylene carbonate; 1,2-propanediol cyclic carbonate; 4-methyl-1,3-dioxolan-2-one; 1,2-propylene carbonate

(±)-4-Methyl-1,3-dioxolan-2-one · [108-32-7]

UNII 8D08K3S51E · PubChem CID 7924

C4H6O3 · 102.09

Solvent, humectant

Typical concentrations: — · Dosage forms: Semi-solid

Used mainly as a solvent in oral and topical formulations. In topical products it has been combined with propylene glycol to dissolve corticosteroids, and in hard gelatin capsules it serves as a non-volatile, stable liquid carrier for the drug. For low-dose drugs, dissolving the drug in propylene carbonate and spraying the solution onto a carrier powder or granules can improve content uniformity. It is also used in cosmetics; the level used varies widely with the formulation.

A clear, colourless, mobile liquid with a faint odour. It is a cyclic carbonate ester of propylene glycol and is a highly polar aprotic solvent.

Boiling point

≈ 242 °C

Melting point

≈ −49 °C

Density

≈ 1.2 g/cm³ at 20 °C

Solubility

soluble in water (about 1 in 5); miscible with acetone, chloroform, ethanol (95%), ether and ethyl acetate

Stable under normal storage conditions. In the presence of acids or bases, and especially at high temperature, it hydrolyses to propylene glycol and carbon dioxide. Store in a well-closed container in a cool, dry place.

Incompatible with strong acids, strong bases and strong oxidising agents.

Produced industrially by the catalysed reaction of propylene oxide with carbon dioxide under pressure; the crude product is purified by distillation.

Used in oral and topical pharmaceutical products and in cosmetics, where it is generally regarded as having low toxicity. It may cause mild skin and eye irritation, and the neat liquid can irritate the mucous membranes.

Observe normal precautions for the quantity handled. Eye protection and gloves are recommended. It is a combustible liquid and should be kept away from sources of ignition.

Included in the FDA Inactive Ingredient Database (oral capsules; topical preparations).

Propylene glycol.

Because it is non-volatile and does not readily attack gelatin, propylene carbonate is useful as a liquid fill solvent where ethanol or water would be unsuitable. Its high polarity also makes it a good solvent for many poorly water-soluble drugs.