Lanolin is the name given to the refined wool grease. Wool grease is a natural wax secreted by the sebaceous glands of sheep covering the wool fibers. It protects the wool from the weather, waterproofing the fibers and avoiding moisture accumulation. After rigorous refining processes, lanolin is obtained: a yellow unctuous product, solid at room temperature with a faint characteristic odor. Lanolin is widely used in cosmetic and pharmaceutical applications; being an excellent emollient and having strong emulsifying properties. Although lanolin is being used since ancient times; the name lanolin is used since the XIX Century when the industrial production started.

History

Wool grease was used in the ancient Greece for waterproofing tents and garments. Wool grease is mentioned in De Materia Medica from Discorides under the name Oesypus. Also Pliny the Elder mentions wool grease in his Naturalis Historia. It was also included in the Dispensarium Coloniense in 1565, in a german  traduction of the Farmacopea Augustana in 1694 and the Spanish Pharmacopoeia in 1700. It was also included in the German Pharmacopoeia 4th Edition from 1890 and the British Pharmacopoeia in 1885, Addendum 1890. The product was named lanolin by Otto Braun in a German patent from 1882. This patent described the recovery of wool grease from the scouring waters using a centrifuge. Initially lanolin was a trademark, becoming later a generic name.

Applications

Lanolin is widely used in pharmaceutical, personal care and industrial products. It’s commonly used in creams, ointments, lotions, shampoos, hair conditioners and other cosmetic products. Industrial applications include rust preventers, plastifiers, lubricants,  adhesives, leather finishing and textiles. Pharmaceutical applications include cholesterol and vitamin D3 production.

Chemistry

Chemically is a wax, a complex mixture of esters of long chain fatty acids with high molecular weight alcohols. 90-95% of lanolin is esters and 5-10% is free alcohols, in addition, it contain small quantities of  free fatty acids and hydrocarbons. Wool wax is a much more complex matrix than animal fats or vegetable oils, with a molecular mass distribution spanning 100-2000 Da. More than 170 different fatty acids and more than 70 alcohols of high molecular weight have been found in lanolin. Free fatty acids range from C9 to C33,  in the “normal”, “iso” and ”ante-iso” types. Approximately 30% is alpha-hydroxyacids. The alcoholic fraction is contains sterols, triterpene alcohols, aliphatic alcohols, mono-alcohols, diols and polyols. Approximately 35% of the alcoholic fraction is cholesterol

Refining and purity

Refining is the industrial process used to obtain lanolin without impurities, bleached and deodorized.