Cream (pharmaceutical)
A skin cream is a semi-solid spreadable composition for application to the skin, and consists of an aqueous ( hydrophilic) and an oily or grease ( lipophilic ) component of the emulsion is a dispersed manner in the other.
Physical structure
Physically creams have a complex structure, which mainly combines the structures of emulsions and gels. A distinction is made with water washable creams (hydrophilic cream of the O / W type ) in which the oily constituents dispersed present in a coherent aqueous phase from the non- washable creams (lipophilic cream of the W / O) type, in which the aqueous component in the oil phase is dispersed. There are also creams that are neither clear nor the o/w- the W / O type can be assigned, but which consist of gel-like, coherent distributed into each of lipophilic and hydrophilic phase ( amphiphilic cream). Also structures of a multiple emulsion of the W / O / W emulsion are discussed. Here, the inner phase will again be in the form of an emulsion. In the inner oil phase smallest water droplets are again stored. This type of emulsion is to combine the advantages of W / O emulsions and O / W emulsions in itself.
A low water content gives a cream ointment-like properties, the incorporation of large amounts finely a subdivided solids leads to a pasty consistency.
Must be differentiated from creams to lotions (thick - to thin-liquid emulsions, also known as skin milk). Colloquial terms such as cream, ointment, gel or lotion be used partly across.
History
1911 Before contained creams and other cosmetic products animal fats, these decomposed but have been rancid.
1890 Oscar Troplowitz bought the company Beiersdorf in Hamburg. In 1911 he developed with the chemist Isaac Lifschütz and dermatologist Paul Unna the first water-in -oil emulsion for skin care. Lifschütz wool wax alcohols used ( Eucerit ) as an emulsifier. Beiersdorf Nivea gave this cream the name (Latin nix, genitive nivis = snow).
Function and Applications
Lipophilic creams from the W / O type pull swiftly through the hydrophobic layers of the skin into the skin. You are a light occlusion, since the outer oily phase forms a film on the skin. The release of water (evaporation ) of the skin is inhibited, in consequence of the drying out is prevented and the top layers of skin swell due to water accumulation on. W / O creams are preferred sebostatic for care ( "dry" ) used skin.
Hydrophilic creams from O / W type cause a lower Hautfettung skin and are therefore used more for the care of seborrheic ( " fatty "). Unlike the creams of the W / O type they are non-occlusive, but support the water-binding capacity of the skin by supplying moisture-binding substances such as glycerol, lactic acid or urea. In contrast, an unfavorable composition through increased water evaporation ( " wicking " ) promote drying of the skin.
In addition to the purely nourishing skin cream that can be as required by either the lipophilic or hydrophilic type, there are creams with special functions, which are achieved by the incorporation of appropriate materials. Such as sunscreen, in which a UV light stabilizer is incorporated; the barrier cream that protects the addition of silicone oil ( dimethicone ) against aggressive substances (eg cleaning products, special industrial materials); or the baby cream that obtained by the content of zinc oxide a special protection for the skin in the diaper area. "Anti -aging creams ' contain substances that are intended to prevent premature skin aging. Creams are used not only in cosmetics but also as a basis for the skin to be applied to drugs.
Starting materials in the manufacture of cream
Typical components of the lipophilic phase are based on hydrocarbons ( "Petroleum " ) based waxes or synthetic glycerides. Even vegetable fats and oils ( cocoa butter, almond oil, peanut oil, and others), and animal waxes ( wool wax, bees wax) are used. Partial chemically modified oils (hydrogenated castor oil, hydrogenated soybean oil) are used because of their better durability and consistency. To stabilize the emulsion type cream structures is one emulsifiers to: depending on either the O / W type ( polysorbates, macrogol ethers, fatty alcohol sulfates, and others) or the W / O type ( wool wax alcohols ( Eucerit ), sorbitan fatty acid esters, monoglycerides ).
Creams with a high water content, especially O / W creams that are susceptible to the microbial spoilage and therefore must be conserved ( sorbic acid, parabens). Creams can also contain antioxidants ( butylated hydroxytoluene, α -tocopherol), in order to preserve sensitive ingredients according to prior to oxidation by atmospheric oxygen.
Furthermore, creams humectant Konsistenzverbesserer, Spreitverbesserer and perfume substances.
The ingredients used are now used on packages of cosmetic products according to an international Directive (INCI).
Brands
The oldest and best known brands in Germany for skin creams are " Nivea ", " JOHNSON " and " Florena ". In the course of time, all the skin care lines to the main product " skin cream " developed.