Sodium acetate

• BPSodium Acetate
• Ph. Eur.Sodium Acetate Trihydrate
• USP–NFSodium Acetate

Acetic acid, sodium salt; natrii acetas trihydricus; sodium ethanoate; E262

Sodium acetate trihydrate · [127-09-3]

UNII NVG71ZZ7P0 · PubChem CID 517045

C2H3NaO2·3H2O (trihydrate); C2H3NaO2 (anhydrous) · 136.08 (trihydrate); 82.03 (anhydrous)

pH adjuster, buffering agent

Typical concentrations: — · Dosage forms: Liquid, Sterile (parenteral/ophthalmic)

Sodium acetate is used, usually together with acetic acid, to prepare acetate buffers in the pH range of about 3.8–5.8 for injections, ophthalmic, oral and topical preparations. It is also used as an electrolyte source and systemic alkalising agent in parenteral nutrition and in haemodialysis and peritoneal dialysis solutions, where acetate is metabolised to bicarbonate. Buffer concentrations are typically low, of the order of 0.1–1% w/v.

Colourless, transparent crystals or a white granular crystalline powder, with a faint acetic odour and a saline taste. The trihydrate effloresces in warm, dry air; the anhydrous form is hygroscopic.

pKa (acetic acid)

4.76 at 25 °C

pH

7.5–9.2 (5% w/v aqueous solution)

Melting point

trihydrate melts in its water of crystallisation at about 58 °C and becomes anhydrous above about 120 °C

Solubility

very soluble in water; soluble in ethanol

Stable when stored in an airtight container. Aqueous solutions can be sterilised by autoclaving.

Incompatible with strong oxidising agents and strong acids. As an alkaline salt it may precipitate drugs that are poorly soluble at higher pH, and acetate ions may react with some metal salts.

Made by neutralising acetic acid with sodium carbonate or sodium hydroxide and crystallising the trihydrate from the solution.

Sodium acetate is a normal metabolic intermediate and is regarded as non-toxic at the concentrations used as an excipient. Excessive parenteral administration can cause metabolic alkalosis and sodium overload, so the acetate and sodium load of large-volume infusions must be taken into account.

Observe normal precautions for the quantity handled. Eye protection and gloves are recommended.

GRAS listed. Accepted as a food additive in Europe (E262). Included in the FDA Inactive Ingredient Database (injections, ophthalmic, oral and topical preparations) and in parenteral and non-parenteral medicines licensed in Europe.

Acetic acid; potassium acetate; sodium citrate dihydrate; sodium lactate.

Specify which form (trihydrate or anhydrous) is used, since the trihydrate contains about 40% water and quantities must be corrected accordingly. Acetate buffers have their greatest capacity close to pH 4.8.