Sodium lauryl sulfate

• BPSodium Laurilsulfate
• JPSodium Lauryl Sulfate
• Ph. Eur.Sodium Laurilsulfate
• USP–NFSodium Lauryl Sulfate

Dodecyl sodium sulfate; natrii laurilsulfas; SDS; sodium dodecyl sulfate; sodium laurilsulfate; sodium monododecyl sulfate; Texapon K12

Sulfuric acid monododecyl ester sodium salt (mixture of sodium alkyl sulfates consisting chiefly of sodium dodecyl sulfate) · [151-21-3]

UNII 368GB5141J · PubChem CID 3423265

C12H25NaO4S · 288.38

Surfactant, emulsifier, Lubricant

Typical concentrations: 1–2% as tablet lubricant · Dosage forms: Solid, Semi-solid

An anionic surfactant used in a wide range of non-parenteral products: as an emulsifier (0.5–2.5%), as a detergent in medicated shampoos (about 10%), in skin cleansers (about 1%), as a solubiliser (above about 0.25%), as a tablet lubricant (1–2%) and as a wetting agent in tablets, capsules and dentifrices (1–2%). It is also used in dissolution media for poorly soluble drugs and as a wetting agent to improve drug release.

White or cream to pale yellow crystals, flakes or powder with a smooth feel, a soapy, bitter taste and a faint odour of fatty substances. The pharmacopoeias require not less than 85% of sodium alkyl sulfates calculated as C12H25NaO4S.

HLB

about 40

Critical micelle concentration

about 8.2 mmol/L (about 0.23% w/v) in water at 20 °C

pH

7.0–9.5 (1% w/v aqueous solution)

Melting point

about 204–207 °C (pure substance)

Solubility

freely soluble in water, giving an opalescent solution; practically insoluble in chloroform and ether

Stable under normal storage conditions. In solution it is hydrolysed under strongly acidic conditions (below about pH 2.5) to lauryl alcohol and sodium bisulfate, a reaction accelerated by heat. Store in a well-closed container away from strong oxidisers, in a cool, dry place.

Reacts with cationic surfactants and cationic drugs, causing loss of activity or precipitation. Incompatible with salts of polyvalent metal ions such as aluminium, lead, tin and zinc, and precipitates with potassium salts. Solutions are slightly corrosive to mild steel, copper, brass and aluminium.

Lauryl (dodecyl) alcohol, obtained from coconut or palm kernel oil or by synthesis, is sulfated with sulfur trioxide or chlorosulfonic acid, and the resulting acid ester is neutralised with sodium hydroxide or sodium carbonate.

Moderately toxic if swallowed in large amounts, causing gastrointestinal irritation. It is irritant to the skin, eyes and mucous membranes in a concentration-dependent way and can damage the skin barrier with repeated exposure; it is often used as a model irritant in skin testing. It may also increase the permeability of mucosae and skin to other substances.

The fine powder is irritant to the eyes and respiratory tract. Wear eye protection, gloves and a dust mask or respirator, and handle in a well-ventilated area; low-dust needle or granular grades are available.

Permitted as a direct food additive in the USA for specified uses. Included in the FDA Inactive Ingredient Database (dental preparations, oral capsules, suspensions and tablets, topical and vaginal preparations) and in non-parenteral medicines licensed in Europe.

Sodium laureth sulfate; magnesium lauryl sulfate; sodium cetostearyl sulfate; docusate sodium.

Its strong wetting effect can improve the dissolution of hydrophobic drugs from tablets and capsules, but it can also cause foaming during wet granulation and coating. When it is used in dissolution media, check for interactions with gelatin capsule shells and cationic drugs.