Lanolin

• BPWool Fat
• JPPurified Lanolin
• Ph. Eur.Wool Fat
• USP–NFLanolin

Adeps lanae; anhydrous lanolin; purified lanolin; refined wool fat; wool fat; wool wax; E913

Lanolin (purified wax-like substance from the wool of sheep) · [8006-54-0]

Polymer, mixture or material of variable composition — no single molecular formula applies.

Semi-solid base, emollient

Typical concentrations: — · Dosage forms: Semi-solid

Used widely in topical creams and ointments. It is an emollient and occlusive base and, when mixed with suitable vegetable oils or soft paraffin, forms water-in-oil emulsions; it can take up about twice its own weight of water without separating. It is a constituent of many ointment bases, including eye ointments, and of cosmetics.

A pale yellow, unctuous, waxy substance with a faint characteristic odour; melted lanolin is a clear or almost clear yellow liquid. It is a complex mixture of esters and polyesters of high-molecular-weight alcohols (sterols such as cholesterol and lanosterol, and aliphatic alcohols) with fatty acids.

Melting range

about 38–44 °C

Water absorption

can absorb about twice its weight of water

Acid value

not more than 1.0

Solubility

practically insoluble in water; freely soluble in chloroform and ether; sparingly soluble in cold ethanol, more soluble in boiling ethanol

Lanolin can autoxidise on storage; an antioxidant such as BHT may be added. Prolonged or excessive heating darkens it and produces a strong odour. Store in a well-filled, airtight, light-resistant container in a cool place.

Lanolin may contain pro-oxidants that can affect the stability of some drugs.

Raw wool is scoured with detergent solutions and the wool grease is recovered from the washings, usually by centrifugation. It is then refined (washed, bleached and deodorised) to give pharmaceutical-grade lanolin; pesticide residues are limited by the pharmacopoeias.

Generally regarded as non-toxic, but lanolin can cause hypersensitivity and allergic contact dermatitis, mainly attributed to its free alcohol fraction. Grades with reduced free lanolin alcohols are offered as hypoallergenic.

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

Accepted as a food additive in Europe (E913, as a glazing agent). Included in the FDA Inactive Ingredient Database (ophthalmic, topical and vaginal preparations) and in non-parenteral medicines licensed in Europe.

Hydrogenated lanolin; hydrous lanolin; lanolin alcohols; liquid lanolin; modified lanolin.

Hydrous lanolin (hydrous wool fat) contains about 25–30% water and is easier to incorporate into creams. Allergic reactions to lanolin should be considered when formulating products for eczematous or damaged skin.