Potassium sorbate

• BPPotassium Sorbate
• Ph. Eur.Potassium Sorbate
• USP–NFPotassium Sorbate

2,4-Hexadienoic acid potassium salt; kalii sorbas; potassium (E,E)-hexa-2,4-dienoate; Sorbistat-K; E202

(E,E)-Hexa-2,4-dienoic acid potassium salt · [24634-61-5]

UNII 1VPU26JZZ4 · PubChem CID 23676745

C6H7KO2 · 150.22

Antimicrobial preservative

Typical concentrations: 0.1–0.2% · Dosage forms: Liquid, Semi-solid

An antimicrobial preservative used in oral and topical pharmaceutical products, cosmetics and foods, usually at about 0.1–0.2%. Its activity, mainly against yeasts and moulds and less against bacteria, is due to undissociated sorbic acid, so it is most effective in formulations with a pH below about 6. It is often used together with other preservatives.

White crystals, crystalline powder or granules with a faint characteristic odour.

Solubility

very soluble in water; slightly soluble in ethanol; practically insoluble in most oils

pKa (sorbic acid)

4.76

Effective pH range

below about 6, most active at pH 4–5

Melting point

decomposes at high temperature (above about 270 °C)

More stable than sorbic acid in the solid state, but aqueous solutions are susceptible to oxidation, particularly when exposed to light, with discolouration and loss of activity. Store in an airtight, light-resistant container in a cool, dry place.

Incompatible with strong oxidising agents. Some activity can be lost by sorption onto plastic containers and by interaction with nonionic surfactants. In acidic formulations it is converted to sorbic acid, which may precipitate if its solubility is exceeded.

Prepared by neutralising sorbic acid with potassium hydroxide or potassium carbonate; sorbic acid itself is made synthetically, for example from crotonaldehyde and ketene.

Of low toxicity; sorbic acid is metabolised like other fatty acids. Skin irritation and occasional contact sensitisation have been reported after topical use. EFSA and JECFA have allocated group ADIs for sorbic acid and its potassium salt.

Observe normal precautions for the quantity handled. The dust may irritate the eyes, skin and respiratory tract; eye protection, gloves and a dust mask are recommended.

GRAS listed. Accepted as a food additive in Europe (E202). Included in the FDA Inactive Ingredient Database (oral and topical preparations) and in non-parenteral medicines licensed in Europe.

Calcium sorbate; sodium benzoate; sorbic acid.

Potassium sorbate is preferred to sorbic acid when a readily water-soluble preservative is needed; about 1.34 g of potassium sorbate provides the same amount of sorbic acid as 1 g of the acid.