Lanolin

Wool wax (also known as lanolin, wool grease, lat adeps lanae ) is the secretion from the sebaceous glands of sheep, which is obtained during the washing of sheep's wool.

Lanolin

Lanolin is the INCI name of wool wax and thus used internationally. To be distinguished is called the wool wax of pharmaceutically used wool wax containing water-absorbent ointment bases, which according to the Pharmacopoeia nomenclature also lanolin (Latin Lanolinum ). Therefore, in the pharmaceutical sector is more, the term wool wax and more in all other areas, the term lanolin common.

Composition

Bifunctional groups, due to the occurring of the hydroxy (approx. 32% of the fatty acid fraction ) and dihydroxy alcohols ( approximately 7% of the alcoholic fraction ) consists of a mixture of lanolin predominantly long chain esters, di- esters and hydroxy esters. On its hydrolysis 69 aliphatic alcohols ( C14 - C36 ), 6 sterols ( cholesterol, dihydrocholesterol, lanosterol, dihydrolanosterol, agnosterol, Dihydroagnosterol ) and 138 fatty acids (C8 - C41 ) have been isolated. Assuming that only monoester compounds are present, already resulting therefrom over ten thousand possible combinations of ester compounds; The actual number is not known. In pharmaceutical lanolin, up 0.5 % free fatty acids (eg European Pharmacopoeia, acid number <1). The content of free alcohols (up to 12 %) is not limited.

Extraction

The lanolin in ancient times as Oesypus medically used came later forgotten and was only reintroduced in 1885 by Oskar Liebreich as purified wool fat in the medicinal treasure. Wool grease is so far a misnomer, as fats are fatty acid esters of glycerol, whereas ester waxes represent other alcohols. The crude lanolin found in wool sweat of the sheep, and go when washing the wool initially in the wash water, and then separated by the addition of acids therefrom deposited by separators.

For purification of Rohwollwachs several treatment steps are necessary because the impurities to be removed entirely different in nature. The Rohwollwachs is first treated with dilute Salz-/Phosphorsäure to implement any water-soluble and fat-soluble soaps in free fatty acids. At the same time acid-soluble impurities are removed. The aqueous phase is removed and the remaining raw wool wax washed with hot water until it is neutral.

The free fatty acids are first converted by neutralization with sodium carbonate or sodium hydroxide preferably in soaps. Since the resulting sodium soaps are poorly soluble in water, either ethanol or 2 -propanol is added as an additional solvent in a concentration of 20 to 30%. To ensure a stoichiometric reaction of the fatty acids, caustic soda is added in excess. Also disruptive emulsion formation is reduced because of the high ion concentration. To a large excess of sodium hydroxide solution has to be avoided since it leads to an alkaline hydrolysis of the ester. After the soaps have formed, the aqueous layer is removed and the wool wax then washed with hot water or dilute alcohol until it is completely freed from the remaining soap. Finally, the product is dried. Previously removed and soap solution is not discarded, but usually acidified with sulfuric acid, in order to regain from the soaps, the free fatty acids.

For the avoidance of tick infestation is treated sheep after shearing with pesticides, which accumulate as a good fat-soluble substances in wool wax. To remove pesticides and PAH residues, followed by a short path distillation under high vacuum, which also causes a deodorization. In this process, the amount of the naturally occurring in lanolin free fatty alcohols that contribute to good water / oil emulsion property of wool wax significantly reduced. This can lead to a correspondingly reduced water intake.

Detergents or detergent residues are largely removed from the Rohwollwachs by these treatments. A further reduction can be achieved by additional extraction with a polar solvent such as 45 percent ethanol or 2-propanol, or by treatment with an adsorbent such as activated clay or activated carbon, which then must be followed by a filtration.

For potency and purity of wool wax the color is no indicator, but a bright color is considered more aesthetic. It can be achieved by chemical or physical bleaching. Traditionally, the oxidative bleaching with hydrogen peroxide, but has the undesirable side effect, lead to a significant peroxide, which can be interpreted as rancidity. There is need for a careful control with subsequent treatment to remove the organic peroxide residues. After bleaching, drying the wool wax with dry air or by applying a vacuum. The finished treated wool wax are to conclude max. 200 ppm of BHT ( butylated hydroxytoluene ) was added as an antioxidant (if required ). After the final analysis, the batch is filtered and bottled.

Properties

The anhydrous lanolin (Latin adeps lanae anhydricus ) of the European Pharmacopoeia, a pale yellow, ointment-like mass of weak, characteristic odor, insoluble in water, and melts at 40 ° C.

Lanolin is a mixture of liquid and solid waxy masses. Chemically, wool wax is a mixture of cholesterol and fatty acid esters and next Isocholesterin contains free alcohols and hydrocarbons. The esters are composed of long-chain fatty acids and wax acids, bound to fatty alcohols, wax alcohols, cholesterol, lanosterol and other sterols. Pure wool wax may only leave a very low ash residue and contain only traces of free acid. Alkalis, chlorides and glycerol may not be included.

Lanolin penetrates well into the skin and shows little tendency to become rancid.

Lanolin has the ability to absorb several times its weight in water, thereby forming a water-in -oil emulsion ( W / O emulsion). Responsible for the emulsifying properties of wool wax are included with up to about 10 % of free wool wax alcohols, which may cause allergic reactions with redness and swelling in very rare cases.

From pharmaceutical importance also some good water-absorbent ointment bases on the basis of wool wax, lanolin or composite are hydrous wool wax hot (Latin Cera Lanae cum aqua composita ):

• Lanolin (DAB 10): 15 parts liquid paraffin, 20 parts water, 65 parts Lanolin. It is a yellowish-white, ointment-like mass is separating when heated in a water bath in an aqueous and an oily layer floating on this, and should, after drying at 100 ° C not more than 26 % lose weight.
• Lanolin (Ph. Helv 7): 10 parts olive oil, 20 parts water, 70 parts Lanolin
• Composite hydrous lanolin ( ÖAB 90): 10 parts liquid paraffin, 20 parts water, 70 parts Lanolin
• Hydrous wool fat (Ph. Eur ): 25 parts water, 75 parts Lanolin

To make hydrous wool fat supple, sometimes is given to him to olive oil for cosmetic purposes in many essential oils, vanillin and other fragrances.

Wool wax has excellent skin care properties as it can regulate the trans-epidermal water balance. It accelerates wound healing and is therefore included in ointments, creams and baby care creams for damaged skin as well as skin cream. His care property is also used in leather care products. A traditional remedy that uses the skin care properties of lanolin, the natural healing wool.

Use

In cosmetic preparations purified wool wax as a co-emulsifier, strongly adhering lipid and Superfatting used. Lanolin can, as an alternative to petroleum jelly, may be used as a nasal ointment for the care of the mucous membranes. Mixed with chamomile extracts used wool fat as the base material for the production of wound-healing ointment (Example: Kamillosan ointment). In addition, lanolin is also used in technical areas such as for corrosion protection of sheet metal parts and voids in vehicles or ships.