Composition
Lanolin alcohol is lanolin's primary derivative. It consists of a refined mixture of high molecular weight (MW) alcohols (the mean MW is 370).
The main fraction (75%) is composed of sterols and triterpene alcohols, of which cholesterol is the largest individual component (36%), followed by lanosterol, agnosterol and their dihydric derivatives.
Lanolin alcohol is a superior sole emulsifier and powerful emollient.
These alcohols are closely related to the physiological lipids of the stratum corneum, the human skin's 'horny layer'. This results in the excellent epidermal compatibility of lanolin alcohols in skin-care products.
The alcohol mixture also contains branched and unbranched aliphatic alcohols in both mono- and dihydric forms.
To avoid surface autoxidation, traces of butylhydroxytoluene (BHT) are added at the end of the refining process.
Product features
Free lanolin alcohols have a more potent surface activity than the esters in which they are usually bound as a result of their higher polarity. They are the source of the high water absorption capacity of lanolin anhydrous.
Free and refined lanolin alcohol is an even more efficient absorbent, capable of taking up a larger multiple of its weight in water (WW). This makes it one of the most powerful non-ionic water-in-oil (w/o) emulsifying agents available.
Applications
Lanolin alcohols are produced from only the highest-grade wool grease, to meet the numerous pharmacopoeias' strict requirements.
The waxy substance's pale colour and mild scent makes it ideal for use as an emulsifier and stabiliser in cosmetics and toiletries, where whiteness and neutral odour are important.
One of the best-known moisturisers containing lanolin alcohol is Nivea Creme®, which has relied on its emollient effect for nearly a century.
Specification
Acid value (mg KOH/g): <= 2
Saponification value (mg KOH/g): <= 10
Cholesterol content (%): >= 8
Drop point (°C): 50 – 80
Sulphated ash (%): >= 0.2
Loss on drying (%): <= 0.5
Colour (Gardner, 22.5 g/100 ml DCM) <= 7
When blended with cetearyl alcohol as an additional stabiliser, and mineral oil or petrolatum to change consistency, lanolin alcohol acts as a functional component in so-called absorption bases.
Because lanolin alcohol's emulsifying properties are stable in a wide pH range, it can be used in acidic and alkaline w/o emulsions, such as hair bleaching agents.
Another important property is lanolin alcohol's ability to help the wound-healing process. As a result, it has numerous applications in medical and pharmaceutical products.
In addition, lanolin alcohols can function as carrier systems to deliver pharmacologically active substances through the skin.
