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Lanolin (from
Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
'wool', and 'oil'), also called wool yolk, wool wax, or wool grease, is a wax secreted by the
sebaceous gland A sebaceous gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greatest number ...
s of
wool Wool is the textile fibre obtained from sheep and other mammals, especially goats, rabbits, and camelids. The term may also refer to inorganic materials, such as mineral wool and glass wool, that have properties similar to animal wool. A ...
-bearing animals. Lanolin used by humans comes from
domestic sheep Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus ''Ovis'', in everyday usage it almost always refers to domesticated sh ...
breeds A breed is a specific group of domestic animals having homogeneous appearance (phenotype), homogeneous behavior, and/or other characteristics that distinguish it from other organisms of the same species. In literature, there exist several slight ...
that are raised specifically for their wool. Historically, many
pharmacopoeia A pharmacopoeia, pharmacopeia, or pharmacopoea (from the obsolete typography ''pharmacopœia'', meaning "drug-making"), in its modern technical sense, is a book containing directions for the identification of compound medicines, and published by ...
s have referred to lanolin as wool fat ('' adeps lanae''); however, as lanolin lacks
glycerides Glycerides, more correctly known as acylglycerols, are esters formed from glycerol and fatty acids, and are generally very hydrophobic. Glycerol has three hydroxyl functional groups, which can be esterified with one, two, or three fatty acids ...
(glycerol esters), it is not a true fat. Lanolin primarily consists of
sterol Sterol is an organic compound with formula , whose molecule is derived from that of gonane by replacement of a hydrogen atom in position 3 by a hydroxyl group. It is therefore an alcohol of gonane. More generally, any compounds that contain the gon ...
esters instead. Lanolin's
waterproofing Waterproofing is the process of making an object or structure waterproof or water-resistant so that it remains relatively unaffected by water or resisting the ingress of water under specified conditions. Such items may be used in wet environme ...
property aids sheep in shedding water from their coats. Certain breeds of sheep produce large amounts of lanolin. Lanolin's role in nature is to protect wool and skin from climate and the environment; it also plays a role in skin ( integumental) hygiene. Lanolin and its derivatives are used in the protection, treatment, and beautification of human skin.


Composition

A typical high-purity grade of lanolin is composed predominantly of
long chain A polymer (; Greek '' poly-'', "many" + ''-mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic and ...
waxy
ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides are f ...
s (approximately 97% by weight) with the remainder being lanolin
alcohol Alcohol most commonly refers to: * Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom * Alcohol (drug), an intoxicant found in alcoholic drinks Alcohol may also refer to: Chemicals * Ethanol, one of sev ...
s, lanolin
acid In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...
s and lanolin
hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...
s. 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, hydroxyesters, 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 Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis i ...
, fractional solvent
crystallisation Crystallization is the process by which solid forms, where the atoms or molecules are highly organized into a structure known as a crystal. Some ways by which crystals form are precipitating from a solution, freezing, or more rarely dep ...
,
esterification In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides are ...
,
hydrogenation Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic c ...
, alkoxylation and quaternisation. Lanolin derivatives obtained from these processes are used widely in both high-value cosmetics and skin treatment products.
Hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis i ...
of lanolin yields lanolin alcohols and lanolin acids. Lanolin alcohols are a rich source of cholesterol (an important skin lipid) and are powerful water-in-oil
emulsifier An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Although ...
s; they have been used extensively in skincare products for over 100 years. Notably, approximately 40% of the acids derived from lanolin are alpha-hydroxy acids (AHAs). The use of AHAs in skin care products has attracted a great deal of attention in recent years. Details of the AHAs isolated from lanolin can be seen in the table below.


Modern developments

In addition to general purity requirements, lanolin must meet official requirements for the permissible levels of
pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampri ...
residues. The Fifth Supplement of the
United States Pharmacopoeia The ''United States Pharmacopeia'' (''USP'') is a pharmacopeia (compendium of drug information) for the United States published annually by the United States Pharmacopeial Convention (usually also called the USP), a nonprofit organization th ...
XXII published in 1992 was the first to specify limits for 34 named
pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampri ...
s. A total limit of 40  ppm (i.e. 40 mg/kg) total pesticides was stipulated for lanolin of general use, with no individual limit greater than 10 ppm. A second monograph also introduced into the US Pharmacopoeia XXII in 1992 was entitled 'Modified Lanolin'. Lanolin conforming to this monograph is intended for use in more exacting applications, for example on open wounds. In this monograph, the limit of total pesticides was reduced to 3 ppm total pesticides, with no individual limit greater than 1 ppm. In 2000, the
European Pharmacopoeia The ''European Pharmacopoeia'' (''Pharmacopoeia Europaea'', ''Ph. Eur.'') is a major regional pharmacopoeia which provides common quality standards throughout the pharmaceutical industry in Europe to control the quality of medicines, and the su ...
introduced pesticide residue limits into its lanolin monograph. This requirement, which is generally regarded as the new quality standard, extends the list of pesticides to 40 and imposes even lower concentration limits. Some very high-purity grades of lanolin surpass monograph requirements. New products obtained using complex purification techniques produce lanolin esters in their natural state, removing oxidative and environmental impurities resulting in white, odourless,
hypoallergenic Hypoallergenic, meaning "below average" or "slightly" allergenic, is a term meaning that something (usually cosmetics, pets, textiles, food, etc.) causes fewer allergic reactions. The term was first used in 1953 in an advertising campaign for cos ...
lanolin. These ultra-high-purity grades of lanolin are ideally suited to the treatment of dermatological disorders such as
eczema Dermatitis is inflammation of the skin, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved can ...
and on open wounds. Lanolin attracted attention owing to a misunderstanding concerning its sensitising potential. A study carried out at New York University Hospital in the early 1950s had shown about 1% of patients with dermatological disorders were allergic to the lanolin being used at that time. By one estimate, this simple misunderstanding of failing to differentiate between the general healthy population and patients with dermatological disorders exaggerates the sensitising potential of lanolin by 5,000–6,000 times. The European Cosmetics Directive, introduced in July 1976, contained a stipulation that cosmetics which contained lanolin should be labelled to that effect. This ruling was challenged immediately, and in the early 1980s, it was overturned and removed from the directive. Despite only being in force for a short period of time, this ruling did harm both to the lanolin industry and to the reputation of lanolin in general. The Cosmetics Directive ruling only applied to the presence of lanolin in cosmetic products; it did not apply to the many hundreds of its different uses in dermatological products designed for the treatment of compromised skin conditions. Modern analytical methods have revealed lanolin possesses a number of important chemical and physical similarities to human
stratum corneum The stratum corneum (Latin for 'horny layer') is the outermost layer of the epidermis. The human stratum corneum comprises several levels of flattened corneocytes that are divided into two layers: the ''stratum disjunctum'' and ''stratum compac ...
lipids; the
lipids Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include ...
which help regulate the rate of water loss across the
epidermis The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water relea ...
and govern the hydration state of the skin.
Cryogenic In physics, cryogenics is the production and behaviour of materials at very low temperatures. The 13th IIR International Congress of Refrigeration (held in Washington DC in 1971) endorsed a universal definition of “cryogenics” and “cr ...
scanning electron microscopy has shown that lanolin, like human stratum corneum lipids, consists of a mass of liquid crystalline material. Cross-polarised light microscopy has shown the multilamellar
vesicle Vesicle may refer to: ; In cellular biology or chemistry * Vesicle (biology and chemistry), a supramolecular assembly of lipid molecules, like a cell membrane * Synaptic vesicle ; In human embryology * Vesicle (embryology), bulge-like features o ...
s formed by lanolin are identical to those formed by human stratum corneum lipids. The incorporation of bound water into the stratum corneum involves the formation of multilamellar vesicles. Skin bioengineering studies have shown the durational effect of the
emollient A moisturizer, or emollient, is a cosmetic preparation used for protecting, moisturizing, and lubricating the skin. These functions are normally performed by sebum produced by healthy skin. The word "emollient" is derived from the Latin verb ''mo ...
(skin smoothing) action produced by lanolin is very significant and lasts for many hours. Lanolin applied to the skin at 2 mg/cm2 has been shown to reduce roughness by about 35% after one hour and 50% after two hours, with the overall effect lasting for considerably more than eight hours. Lanolin is also known to form semiocclusive (breathable) films on the skin. When applied daily at around 4 mg/cm2 for five consecutive days, the positive moisturising effects of lanolin were detectable until 72 hours after final application. Lanolin may achieve some of its moisturising effects by forming a secondary moisture reservoir within the skin. The barrier repair properties of lanolin have been reported to be superior to those produced by both
petrolatum Petroleum jelly, petrolatum, white petrolatum, soft paraffin, or multi-hydrocarbon, CAS number 8009-03-8, is a semi-solid mixture of hydrocarbons (with carbon numbers mainly higher than 25), originally promoted as a topical ointment for its he ...
and glycerol. In a small clinical study conducted on volunteer subjects with terribly dry (xerotic) hands, lanolin was shown to be superior to petrolatum in reducing the signs and symptoms of dryness and scaling, cracks and abrasions, and pain and itch. In another study, a high purity grade of lanolin was found to be significantly superior to petrolatum in assisting the healing of superficial wounds.


Applications

Lanolin and its many derivatives are used extensively in both the personal care (e.g., high value cosmetics, facial cosmetics, lip products) and health care sectors such as topical liniments. Lanolin is also found in lubricants, rust-preventive coatings, shoe polish, and other commercial products. Lanolin is a relatively common allergen and is often misunderstood as a wool allergy. However, allergy to a lanolin-containing product is difficult to pinpoint and often other products containing lanolin may be fine for use. Patch testing can be done if a lanolin allergy is suspected. It is frequently used in protective baby skin treatment and for sore nipples from breastfeeding. Lanolin is used commercially in many industrial products ranging from
rust Rust is an iron oxide, a usually reddish-brown oxide formed by the reaction of iron and oxygen in the catalytic presence of water or air moisture. Rust consists of hydrous iron(III) oxides (Fe2O3·nH2O) and iron(III) oxide-hydroxide (FeO(OH) ...
proof coatings to
lubricant A lubricant (sometimes shortened to lube) is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, t ...
s. Some sailors use lanolin to create slippery surfaces on their
propeller A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...
s and stern gear to which
barnacles A barnacle is a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosiv ...
cannot adhere. Commercial products (e.g. Lanocote) containing up to 85% lanolin are used to prevent corrosion in marine fasteners, especially when two different metals are in contact with each other and saltwater. The water-repellent properties make it valuable in many applications as a lubricant grease where
corrosion Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engine ...
would otherwise be a problem. 7-Dehydrocholesterol from lanolin is used as a raw material for producing vitamin D3 by irradiation with ultraviolet light.
Baseball player Baseball is a bat-and-ball sport played between two teams of nine players each, taking turns batting and fielding. The game occurs over the course of several plays, with each play generally beginning when a player on the fielding te ...
s often use it to soften and break in their
baseball glove A baseball glove or mitt is a large glove (traditionally made of leather, today other options do exist) worn by baseball players of the defending team, which assists players in catching and fielding balls hit by a batter or thrown by a teammate ...
s (
shaving cream Shaving cream or shave cream is a category of cream cosmetics used for shaving preparation. The purpose of shaving cream is to soften the hair by providing lubrication. Different types of shaving creams include aerosol shaving cream (also kno ...
with lanolin is popularly used for this). Anhydrous liquid lanolin, combined with
paraben Parabens are a class of widely used preservatives in cosmetic and pharmaceutical products. Chemically, they are a series of parahydroxybenzoates or esters of parahydroxybenzoic acid (also known as 4-hydroxybenzoic acid). Parabens are effective ...
s, has been used in trials as artificial tears to treat
dry eye Dry or dryness most often refers to: * Lack of rainfall, which may refer to **Arid regions **Drought * Dry or dry area, relating to legal prohibition of selling, serving, or imbibing alcoholic beverages * Dry humor, deadpan * Dryness (medical) ...
.
Anhydrous lanolin is also used as a lubricant for
brass instrument A brass instrument is a musical instrument that produces sound by sympathetic vibration of air in a tubular resonator in sympathy with the vibration of the player's lips. Brass instruments are also called labrosones or labrophones, from Latin a ...
tuning slides. Lanolin can also be restored to
wool Wool is the textile fibre obtained from sheep and other mammals, especially goats, rabbits, and camelids. The term may also refer to inorganic materials, such as mineral wool and glass wool, that have properties similar to animal wool. A ...
len garments to make them water and dirt repellent, such as for
cloth diaper A cloth diaper (American English) or a cloth nappy or real nappy or a reusable nappy (Australian English and British English) is a reusable diaper made from natural fibers, man-made materials, or a combination of both. They are often made ...
covers. Lanolin is also used in
lip balm Lip balm or lip salve is a wax-like substance applied topically to the lips to moisturize and relieve chapped or dry lips, angular cheilitis, stomatitis, or cold sores. Lip balm often contains beeswax or carnauba wax, camphor, cetyl alcohol, lan ...
products such as Carmex. For some people, it can irritate the lips. Lanolin is sometimes used by people on continuous positive airway pressure therapy to reduce irritation with masks, particular nasal pillow masks that can often create sore spots in the
nostril A nostril (or naris , plural ''nares'' ) is either of the two orifices of the nose. They enable the entry and exit of air and other gasses through the nasal cavities. In birds and mammals, they contain branched bones or cartilages called tur ...
s. Lanolin is a popular additive to
moustache wax Moustache wax is a stiff pomade applied to a moustache as a grooming aid to hold the hairs in place, especially at the extremities. The required product strength (or stiffness) is based on whisker length and the desired style. It can also have re ...
, particularly 'extra-firm' varieties. Lanolin is used as a primary lubricating component in aerosol-based brass
lubricant A lubricant (sometimes shortened to lube) is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, t ...
s in the ammunition reloading process. Mixed warm 1:12 with highly concentrated
ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a hyd ...
(usually 99%), the ethanol acts as a carrier which evaporates quickly after application, leaving a fine film of lanolin behind to prevent brass seizing in resizing dies. Lanolin, when mixed with ingredients such as
neatsfoot oil Neatsfoot oil is a yellow oil rendered and purified from the shin bones and feet (but not the hooves) of cattle. "Neat" in the oil's name comes from an Old English word for cattle. Neatsfoot oil is used as a conditioning, softening and preserv ...
,
beeswax Beeswax (''cera alba'') is a natural wax produced by honey bees of the genus ''Apis''. The wax is formed into scales by eight wax-producing glands in the abdominal segments of worker bees, which discard it in or at the hive. The hive worker ...
and glycerol, is used in various
leather Leather is a strong, flexible and durable material obtained from the tanning, or chemical treatment, of animal skins and hides to prevent decay. The most common leathers come from cattle, sheep, goats, equine animals, buffalo, pigs and hogs ...
treatments, for example in some
saddle soap Saddle soap is a compound used for cleaning, conditioning, and protecting leather. It typically contains mild soap, softening ingredients such as lanolin, and preservatives such as beeswax. It is commonly used on leather footwear, saddles, and ot ...
s and in leather care products.


Production

Crude lanolin constitutes about 5–25% of the weight of freshly shorn wool. The wool from one
Merino sheep The Merino is a breed or group of breeds of domestic sheep, characterised by very fine soft wool. It was established in Spain near the end of the Middle Ages, and was for several centuries kept as a strict Spanish monopoly; exports of the breed ...
will produce about 250–300 ml of recoverable wool grease. Lanolin is extracted by washing the wool in hot water with a special wool scouring detergent to remove dirt, wool grease (crude lanolin), suint (sweat salts), and anything else stuck to the wool. The wool grease is continuously removed during this washing process by
centrifuge A centrifuge is a device that uses centrifugal force to separate various components of a fluid. This is achieved by spinning the fluid at high speed within a container, thereby separating fluids of different densities (e.g. cream from milk) or l ...
separators, which concentrate it into a waxlike substance melting at approximately .


References


External links

* {{E number infobox 910-919 Animal glandular products Waxes Non-petroleum based lubricants