Lanolin

Lanolin (from Latin lāna, ‘wool’, and oleum, ‘oil’), also called wool wax or wool grease, is a wax secreted by the sebaceous glands of wool-bearing animals. Lanolin used by humans comes from domestic sheep breeds that are raised specifically for their wool. Historically, many pharmacopoeias have referred to lanolin as wool fat (adeps lanae); however, as lanolin lacks glycerides (glycerol esters), it is not a true fat. Lanolin primarily consists of sterol esters instead. Lanolin's waterproofing property aids sheep in shedding water from their coats. Certain breeds of sheep produce large amounts of lanolin. There is an inverse correlation between fiber diameter and wool wax content.

Lanolin’s role in nature is to protect wool and skin against the ravages of climate and the environment; it also seems to play a role in skin (integumental) hygiene. Lanolin and its many derivatives are used extensively in products designed for the protection, treatment and beautification of human skin.

A typical high purity grade of lanolin is composed predominantly of long chain waxy esters (approximately 97% by weight) the remainder being lanolin alcohols, lanolin acids and lanolin hydrocarbons.

An estimated 8,000 to 20,000 different types of lanolin esters are present in lanolin, resulting from combinations between the 200 or so different lanolin acids and the 100 or so different lanolin alcohols identified so far.

Lanolin’s complex composition of long chain esters, hydroxy esters, diesters, lanolin alcohols, and lanolin acids means in addition to it being a valuable product in its own right, it is also the starting point for the production of a whole spectrum of lanolin derivatives, which possess wide-ranging chemical and physical properties. The main derivatisation routes include hydrolysis, fractional solvent crystallisation, esterification, hydrogenation, and alkoxylation and quaternisation. Lanolin derivatives obtained from these processes are used widely in both high-value cosmetics and skin treatment products.

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