3. Shampoos Definition A viscous cosmetic preparation with synthetic detergent used for washing hair is called shampoo. Its principle function is to clean the scalp such that it should become free from sebum and foreign substances. Shampoo also makes the hair lustrous and good looking. In olden days detergent soap were used for washing hairs, but nowadays it has been replaced by shampoo. Today shampoo has become an important hair cosmetic for both men and women. However, the detergent and other raw materials selected for shampoo preparation should be nontoxic to tile scalp, eyes etc. Apart from cleaning, shampoo may also be used for medicinal purpose medicated shampoo). (i.e., After preparation each shampoo must be evaluated. Properties:  It should have optimum viscosity such that it facilitates ease during application.  It should have good spreading properties.  It should produce sufficient lather after application.  It should be able to remove waste material such as debris, soil, sebum, dead cells, salts (due to sweat) etc., from the scalp.  It should not form any kind of film on scalp.  It should rinse out completely after washing.  It should produce lather with both hot and cold water.  It should facilitate ease of combing after shampooing.  After drying, the hair should not give rough appearance.  It should provide luster to the hair.  It should produce good odor both before and after shampooing.  It should not produce any kind of irritation or itching to the scalp.  It should not support any microbial growth.  It should be stable and have a half-life of about 2 to 3 years.  It should be economical. 3.1 Types of shampoo Various types of shampoos are available, and they are classified based on their consistency. They are as follows: 1. Clear liquid shampoos 2. Liquid cream shampoos 3. Cream shampoos 4. Gel shampoos 5. Powder shampoos 6. Aerosol shampoos (Foam type) 7. Special shampoos 1. Clear Liquid shampoo: These are clear liquid preparations that are most widely used. They are usually made by using detergent of low cloud point. Alkanolamides can also be used in these preparations. Some of these shampoos may be transparent. Formula Triethanolamine lauryl sulphate (surfactant) Lauricisopropanolamine (foam booster) Perfume, color, preservative Water Quantity for 100 g 50 g 2g q. s 48 g 2. Liquid Cream Shampoos: These are called as lotion shampoos which are modification of clear liquid shampoos. Addition of opacifier such as glycerylmonostearate, glycol stearate etc., to the clear liquid shampoo yields liquid cream shampoo. Solubilising agents such as magnesium stearate is also used to dissolve the added opacifier. Formula Triethanolamine lauryl sulphate (surfactant) Glycerylmonostearate (opacifier) Magnesium stearate (stabilizer) Perfume, color, preservative Water Quantity for 100 g 35 g 2g 1g q. s 62 g 3. Cream Shampoos: These shampoos have a paste like consistency and are packed in a collapsible tube. They find great use in hair salons. They are also available in jars with wide mouth. The paste consistency is developed by addition of alkyl sulphates, also Cetyl alcohol is added, which serves as a builder. Formula Sodium lauryl sulphate (surfactant) Cetyl alcohol (builder) Perfume, color, preservative Water Quantity for 100 g 38 g 7g q. s 55 g 4. Gel Shampoo: These are transparent and thick usually made by incorporating a gelling agent, (e.g., cellulose).There is great use in hair salons and beauty parlors. The principle ingredient is detergent which can be used either alone or in combination with soap. By altering the proportion of detergent, gel of required consistency can be obtained. Addition of methyl cellulose to clear liquid shampoo and its subsequent thickening also gives rise to gel shampoo. Formula Alkyl dimethyl benzyl ammonium chloride Triethanolamine lauryl sulphate (surfactant) Coconut diethanolamide Hydroxyl propyl methyl cellulose Perfume, color, preservative Water Quantity for 100 g 15 g 28 g 7g 1g q. s 49 g 5. Powder Shampoos: As name suggests, it is available in the form of dry powder, initially it was prepared from dry soaps, but nowadays dry synthetic detergents are used for their preparation. Powder shampoo is prepared where addition of water or other solvent reduces the activity of the components, especially in case of medicated shampoo. Nowadays, these shampoos are not used due to the difficulty experienced in their application. Formula Sodium lauryl sulphate (surfactant) Sarcoside Sodium bicarbonate Sodium sulphate Perfume Quantity for 100 g 20 g 5g 10 g 65 g q. s Another formulation called dry shampoo is also a type of powder shampoo. Initially they are applied on to the head and then removed by the brush. it doesn't involve the use of water. They are usually preferred, when the hair are greasy. This formulation usually includes adsorbents. Formula Starch (adsorbent) Talc (adsorbent) Kieselgur (adsorbent) Perfume Quantity for 100 g 15 g 45 g 40 g q. s 6. Aerosol Shampoos (Foam Type): They are called aerosol shampoos because they are packed in aerosol containers .Their formulation, preparation and packing is complicated as an additional propellant is included. The propellant added must be compatible and should not reduce the activity of shampooing ingredients. The container opening is provided with a valve. Shampoo comes out as foam when the valve is pressed .Hence also called as foam type shampoo. Formula Triethanolamine lauryl sulphate (surfactant) Coconut diethanolamide Propellant Perfume, color, preservative Water Quantity for 100 g 60 g 2g 10 g q. s 28 g 7. Special Shampoos: These are the shampoos which are meant for special purpose. They are (a) Medicated Shampoo: These shampoos contain medicinal agents. These agents treat the disorders of the scalp or hair. Examples of medicated shampoos are: Anti-lice shampoo, Antidandruff shampoo, Anti-baldness shampoo etc,. The medicinal agent added should not irritate the sebaceous glands. It should not sensitize the scalp. The degree of itching and scaling should also be reduced. Among all, anti dandruff type of medicated shampoo is most widely used. Formula for which is given below: Formula Triethanolamine lauryl sulphate (surfactant) Thymol (anti dandruff) Camphor (counter irritant) Perfume, color, preservative Water Quantity for 100 g 60 g 0.1 g 0.1 g q. s 38.8 g (b) Conditioner Shampoos: These shampoos serve for hair conditioning. Initially they clean the hair (and scalp) and keep them in smooth and lustrous condition. They also prevent sticking of hairs. Conditioner shampoo nowadays is widely used by both men and women. Most of the conditioners are made from Quaternary ammonium compounds. These compounds have the property of reducing electric charges between the hair, as a result hair become lustrous easily manageable. These compounds can also exhibit a bactericidal effect. Formula Stearyl dimethyl benzyl ammonium chloride Ethylene glycol monostearate Cetyl alcohol Perfume, preservative Water Quantity for 100 g 5.5g 2g 2.5 g q. s 90 g 3.2 Formulation of shampoo Formula of Shampoo contains the following ingredients: Ingredients Examples 1. Surfactants (a) Anionic Surfactants Alkyl sulphates, alkyl ether sulphate (b) Non- ionic Surfactants Alkanolamides (c) Cationic Surfactants Alkyl amines, alkyl imidazolines (d) Amphoteric surfactant Acyl amino acids 2. Foam booster Monoethanolamides, lauramides DEA, cocamide DEA 3. Germicide and agent anti-dandruff Banzalkoniumchloride, cetrimide, selenium sulphide, cadmium sulphide 4. Conditioning agent Lanolin, egg, amino acids 5. Pearlescent agent 4-methyl-7-diethylamino coumarin, 4-methyl-5,7dihydrocoumarin EDTA, citric acid, tripohyphosphate 6. Sequestrants Alginates, polyvinyl alcohol, methyl cellulose 7. Thickeners Herbal fruits or floral fragrance 8. Perfuming agent p-hydroxyl benzoic acid phenyl mercuric nitrate 9. Preservatives FD and C dye 10. Colour 1. Surfactants: The main use of surfactant is to cleanse and to produce foam. They are generally categorized into four types. They are: (a) Anionic Surfactants (b) Non-ionic Surfactants (c) Cationic Surfactants (d) Amphoteric Surfactants (a) Anionic Surfactants: These surfactants have good foaming property, hence they are used as principle surfactant. They are considered as main ingredient of shampoo formulation. Examples of Anionic Surfactants: (i) Alkyl Sulphates: When fatty acids are subjected to catalytic reduction, it results in formation of long chain sulphated derivatives called as Alkyl sulphates. (Example: Lauryl sulphate, Myristyl sulphate). A combination of above two compounds is most widely used because they give foam. Sulphates with lauryl chain are widely used when compared to octyl or decyl chain. Previously, sodium lauryl sulphate was used but now triethanolarnine lauryl sulphate is widely used. (ii) Alkyl polyethylene Glycol Sulphates: These anionic surfactants exhibit good cleaning as well good foaming property. They are alkyl ether sulphate which forms water soluble sodium salt. Solubility of this salt is greater than sodium lauryl sulphate, hence also serves as a solvent for non-polar ingredients. Because of low cost, they are widely used by small manufacturers. (iii) Alkyl Benzene Sulphonates: These surfactants are most widely used in the preparation of washing powder but not in cosmetics (i.e. shampoo). Because they cause excessive cleaning, this may lead to damage of scalp and hair. They nay also lead to hair fall and skin irritation. Although they have deleterious effects, they are used for cleaning of greasy hair. (iv) α- olefin Sulphate: It is an alkyl sulphonate obtained by sulfonation of linear olefin. It produces an excellent foam and the property of foaming is unaffected by sebum and hard water. It produces mild detergent effect without harming the scalp. It is stable at both acid and basic pH and widely used to prepare low pH shampoo. It has low cloud point hence also used to prepare clear liquid shampoo. Apart from the above, other anionic surfactants such as sulphosuccinates, Acyl lactylases etc, are also used. (b) Non-ionic Surfactant: These are considered as secondary surfactants. They are not used to produce foam but used as foam boosters, viscosity inducers, emulsion stabilizers and opacifiers. This is because they have less foaming power. Even though they have good cleaning property, they are not used as principle surfactant. Examples of Non-ionic Surfactants: (i) Poly Alkoxylated Derivatives: These are ethoxylated alcohols and phenols, block polymers, sorbitol ester (polyethoxylated) and polyglyceryl ethers. These derivatives are obtained when hydrogen (labile) containing hydrophobic compound is subjected to polyaddition reaction with either ethylene or propylene oxide. They are stable at wide range of pH. They have stabilizing, emulsifying, pearlescent and foaming properties. They are available at low cost and cause irritation to eye mucosa. However, they are used as mild detergents and impart a good rinsing property. They can also be used in high concentration. (ii) Fatty Acid alkanolamides: These include monoalkanolamides and diethanolamides etc,. Monoalkanolamides are made from long chain fatly acids (i.e., C 14- C16). They are insoluble in water due to their Waxy nature. Hence, they are added directly to detergent solution and dissolved by gentle warming. The detergent solution is made by using principle surfactant to which various ethanolamides are added to serve as.  Solubilising Agent: Example: Lauric Monoethanolamide.  Viscosity Inducing Agent: Example: Lauric Monoethanolamide  Pearlescent and Thickening Agent: Example: Stearic Ethanolamide  Softening and Hair Conditioning Agent: Example: Oleic Ethanolamide.  Foam Boosters. However the ratio of detergent solution to the monoethanolamide must be 100:15 and above this ratio may be harmful to scalp and hair. Whereas diethanolamides are available as low melting point solids or even as simple liquids. They are used as powerful solublizing agents. They solubilize the shampoo ingredients rapidly and more efficiently compared to monoethanolamides. The shampoos containing high soap content and free ethanolamides (Example: Kritchevsky condensation products) must be used with precautions. (iii) Amine Oxides: Amine oxides are obtained by the oxidation of tertiary aliphatic amine with hydrogen peroxide. These compounds possess strong polar linkage between nitrogen and oxygen hence they are also called as polar non-ionic surfactants. They constitutes major group of synthetic surfactants. They are water soluble and compatible with various surfactants. They are added as secondary surfactants because of their conditioning, dam boosting and anti-static property. Coconut and dodecyl dimethylamine oxides are most commonly used for this purpose. (c) Cationic Surfactants: Surfactants that contains positive charge are called as cationic surfactants. They are used as both principle and secondary surfactants. These surfactants are used in low concentrations because they are toxic to eye. Hence, they are considered as secondary surfactants. Apart from the above toxic effect, they also have good foaming and partly cleaning properties. Hence, they are also used as principle surfactants in conditioner shampoos. Examples Cationic Surfactants: (i) Alkylamines: They constitute a major group off, cationic surfactants. They are used in combination with hydrophilic surfactants in order to provide conditioning and anti-static property to the shampoo. However they precipitate when combined with anionic surfactants. Usually they are used in the form of water soluble salts. (ii) Ethoxylated amines: These are nitrogen containing surfactants which are obtained by ethoxylation of long, chain alkylamine. They are waxy in nature with low melting point. Because of their waxy nature; they are also used as viscosity inducer. However their main function is emulsification and hair conditioning. Sometimes, they are also used as foam boosters. Due to their emulsifying property, complete dispersion of various ingredients is achieved. (iii) Alkyl-Betains: These classes of cationic surfactants are obtained from N dimethylglycine. They are readily compatible with majority of surfactants and have following properties.  Enhance the efficiency of Foam. Example: Foam Booster.  Contain Conditioning and Anti-static Property.  Have viscosity inducing property.  Possess good stability.  Non-irritant to skin and eye. Based on the above properties, Alkyl Betains are considered as secondary surfactant . They are also used as principle surfactant in baby shampoo and are often used combination with ionic surfactants. A part from the above, various other cationic surfactants like imidazolines and morphollrx derivatives, tetra alkyl ammonium salts are also used. (d) Amphoteric Surfactants: The surfactants which possess both cationic and anionic charges with respect to acidic and basic media are called as amphoteric solvents. They form zwitterions when the pH of media is neutral .These agents produces a mild action and show compatibility with surfactants .They posses excellent hair conditioning property and hence used as secondary surfactants. Examples Amphoteric Surfactants: (i) Dialkyl Ethylene Diamines: These surfactants are soluble in water and compatible with surfactants. They are used as detergents and to a lesser extent as emulsifier. They are usually prepared as aqueous solution or paste into which remaining shampoo ingredients are added. These agents are combined with anionic surfactants in order to minimize the irritation caused by them .These agents neither enhances nor inhibits the foaming property of the principle surfactant. They are most widely used an anti-irritating agent when anionic compounds are used as principle surfactant. (Anionic surfactants are irritant to eye). These agents also possess conditioner and anti-static property as a result of which the hair becomes smooth and soft .However the pH of the shampoo prepared by using these surfactants must be neutral (i.e., in between 6.5 to 7.5). (ii) N-alkyl Amino Acids: The important compounds of this class are derived from amino acids and asparagine. A compound called N- alkyl-b iminoproperonate is derived from bamino acid and it exhibits good foaming property, possesses slightly alkaline pH by changing the pH to acidic range the manageability of hair is improved. Whereas, The derivatives of asparagine are well compatible with both anionic and cationic surfactants. It also posses the properties like foaming, cleaning and conditioning. Depending upon the pH, these compounds change their nature i.e., they become zwitterions at pH 6 and at neutral pH, they become amine. Solubility of N-alkyl amino acids is greater than they are in the form of sodium salts, whereas the solubility decreases with zwitter ionic form. The foaming property of these agents decreases with decrease in pH. This is because at low pH they become cationated (i.e., cationic form). These agents are highly stable and sometimes also employed as emulsifiers 2. Foam Boosters: The surfactants used in the preparation also serves as foaming agents. They, form rich lather i.e., foam which is stabilized or strengthened by using a substance called foam boosters. The substances like fatty acid alkanolamides, amine oxides are used. They make the foam dense and it to remain for long duration. Usually they are added in quantity of about 2 to 5%. Fatty acids and fatty alcohols when added in a range of 0.25 to 0.50% concentrations, they also act as foam boosters. 3. Germicide and Anti-dandruff Agents: Germicides are the agents which prevent the growth of micro-organism on the scalp whereas anti-dandruff agents are used to eliminate dandruff from the scalp. Examples of Germicides are:  Quaternary ammonium compounds: Example: Benzalkonium Chloride, Cetrimide etc. Examples of Anti-dandruff Agents are:  Selenium Sulphide  Cadmium Sulphide 4. Conditioning Agents: These agents improve the condition of hair. These agents have the property of reducing, electric charges the hair, as a result, hair become lustrous and hence easily manageable. These agents also exhibit a bactericidal effect. They make the hair silky and shiny. Most commonly used conditioning agents are lanolin, oils, herbal extracts, egg, amino acids etc. Among the above; amino acid gives an efficient conditioning effect. 5. Pearlescent Agent: these agents are usually added as adjuvants to the conditioning agents. They improve the conditioning property. Addition of these agents also imparts brightness to hair. They make the preparation transparent or opaque; hence they are also called as opacifying agents. The commonly used pearlescent agents are alkanolamides and coumarins like 4-methyl-7-diethyl amino coumarin, 4-methyl-5, 7-dihydrocoumarin etc. Also alcohols and phosphates improve transparent solubilization. 6. Sequestrants: These are complex forming agents. They form complex with metal ions like calcium and magnesium. Surfactant are liable to form complex with the metals present in water i.e., calcium and magnesium. Hence addition of Sequestrants prevents complex formation between metal and surfactant. The Sequestrant itself forms complex with the metal ions. Thus, it prevents the formation of film on the scalp i.e., the film formed by surfactant and metal ions. The commonly used Sequestrants are EDTA, citric acid etc,. 7. Thickening Agents: These agents are usually added to make the preparation thick i.e. viscous. Such viscous preparation facilitates ease of handling. Also, they prevent wastage during application. Already the addition of various agents, such as surfactants, foam boosters etc make the preparation viscous even though thickening agent is added. Substances like methyl cellulose, alginates polyvinyl alcohol, polyethylene glycol etc are commonly used to adjust the viscosity of a shampoo. 8. Perfumes: Addition of these agents imparts good fragrance to the shampoo. It also neutralizes the undesirable odour of other ingredients of formulation especially surfactants. Nowadays it has become an important factor for consumer satisfaction. The selected perfumes must be such that they should retain good smell for fixed period of time even after shampooing. The added perfumes should not affect the solubility and stability of the preparation. They are usually obtained from natural sources such as flowers, fruits, herbs etc. 9. Preservatives: These agents have the ability to prevent the growth of micro-organisms. They are usually added to maintain the stability of the preparation for a desired period of time. Shampoo is a wet preparation that provides a media for various micro organisms hence addition of preservative is essential. Preservative used should not cause any irritation to the scalp. Para-hydroxybenzoic acid and phenyl mercuric nitrate are commonly used preservatives. 10. Colour: Addition of colour gives pleasant appearance to the preparation. Various FD & C dyes are used for colouring the preparation. The added colour must be water soluble and it should not impart any colour to hair or scalp.