Surfactants, are wetting agents that lower the surface tension of a liquid, allowing easier spreading and dispersion, and can also lower the interfacial tension between two liquids.

1. SURFACTANTS
Presented by- Jaskiran Kaur
Guided by – Dr. P.S. Rajinikanth
Department of Pharmaceutical Sciences
Babasaheb Bhimrao Ambedkar University Lucknow
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2. CONTENTS
Introduction
How do cosmetic surfactants work?
Classification of Surfactants
Applications of surfactants in
cosmeceuticals
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3. INTRODUCTION
• Surfactants, are wetting agents that lowers the
surface tension of a liquid, allowing easier
spreading and dispersion, and can also lower the
interfacial tension between two liquids.
• The term surfactant was coined by Antara
Products in 1950.
• Surfactants are usually organic compounds that
are amphipathic, as they contain both
hydrophobic groups ("tails") and hydrophilic
groups ("heads"). Therefore, they are soluble in
both organic solvents and water.
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4. • Surfactants are indicated by the presence of both polar and non-polar region.
• A surfactant molecule are formed by two parts with different affinities for the
solvents. One of them has affinity for water (polar solvents) and the other for oil
(non-polar solvents).
• Surfactants are substances that create self-assembled molecular clusters called
micelles in a solution (water or oil phase) and adsorb to the interface between a
solution and a different phase (gases/solids).
• To show these two physical properties, a surfactant must have a chemical
structure with two different functional groups with different affinity within the
same molecule.
• Usually the molecules of the substances called surfactants have both an alkyl
chain with 8–22 carbons.
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5. How do cosmetic surfactants work?
• When surfactants are put into solutions, the molecules have a tendency to line up
in a certain way depending on the solution composition, the concentration of the
surfactant, and the temperature.
• In a water solution with extremely low surfactant concentrations, the molecules
tend to bounce around randomly without forming structures. But at the Critical
Micelle Concentration (CMC) they arrange themselves in spherical structures
called micelles.
• On the outer layer of the spheres are the hydrophilic parts of the surfactant
molecule and on the inner layer are the lipophilic parts.
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6. Representation of micelles formation at CMC
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7. Classification of Surfactants
Types of surfactants
Anionic
Surfactant
Cationic
Surfactant
Non-ionic
Surfactant
Amphoteric/
Zwitter-
ionic
Surfactant
Polymeric
Surfactant
Silicone
Surfactant
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9. Anionic surfactants
• In solution, the head is negatively charged.
• These surfactants are the most widely used type of
surfactant for preparing shampoos because of its excellent
cleaning properties and high hair conditioning effects.
• Anionic surfactants are particularly effective at oily
cleaning and oil/clay suspension. Still, they can react in
the wash water with the positively charged water
hardness ions (calcium and magnesium), which can lead
to partial deactivation.
• These are the most common surfactant in general use
(detergents, cleaners, etc.) and many find use in emulsion
polymerization. This is because of their affinity for
hydrogen bonding with the aqueous medium.
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10. • Most of the anionic surfactants are carboxylate, sulfate and sulfonate
ions .
• The straight chain is a saturated /unsaturated C12-C18 aliphatic group.
• There are five subgroups of anionic surfactants:
1. Alkali metal and ammonium soaps,
2. Divalent and trivalent metal soaps,
3. Amine soaps,
4. Alkyl sulphates
5. Alkyl phosphate anionic surfactants.
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11. 1. Alkali metal soaps: sodium, potassium or ammonium salts of long chain fatty
acids such as oleic, stearic and ricinoleic acid and they produce oil in water
emulsion. Eg Sodium stearate.
2. Divalent and trivalent surfactants: calcium oleate (w/o) are water in oil
emulsifying surfactant.
3. Amine surfactants: triethanolamine oleate surfactant is preferentially used for
pharmaceutical applications. They form oil in water emulsion.
4. Alkyl sulphate surfactants: are the esters of fatty alcohols and sulphuric acids.
Most widely used surfactants are sodium lauryl sulphate(SLS). They are oil in
water emulsifying agents.
5. Alkyl phosphates : similar to that of alkyl sulphates but they have their alcohols
phosphate instead of sulphated. They are mostly sued to prepare oil in water
emulsion creams.
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12. Cationic surfactants
• In solution, the head of the cationic surfactant is
positively charged.
• Cationic surfactants are quartenary ammonium
compounds.
• They are mostly used for their conditioning purposes in
cosmetic.
• The primary cationic surfactant agents include
quaternized surfactants (quats), cationic polymers.
• Quats (also known as cationic surfactants) and cationic
polymers remain on the hair via electrostatic interactions.
• They are attracted to the negatively charged, damaged
protein sites on the hair.
• This positive/negative interaction prevents them from
being removed.
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Quats

13. • In addition, cationic surfactants can destabilize biological membranes due to the
interaction of their cationic groups with the negatively charged phospholipids on
the cell membranes. This results in their germicidal activity.
• The quaternary ammonium and pyridinium cationic surfactants have bactericidal
activity against a wide range of gram-positive and some gram-negative
organisms and are commonly used as preservatives .
• Cationic surfactants may also be used on the skin for cleansing of wounds.
• Solutions containing 0.1 % – 1 % cetrimide are used for cleaning the skin,
wounds, and burns, as well as for cleaning contaminated vessels.
• Dilute solution of benzalkonium chloride may be used for the preoperative
disinfection of the skin and mucous membranes, for application to burns and
wounds.
• Benzalkonium chloride is also used as a preservative in eye drops.
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14. • Mostly used cationic surfactants are cetrimide.
• Other cationic surfactants are benzalkonium chloride, cetylpyridinium,
Cetrimonium Chloride, Polyquaternium-10chloride .
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Cetrimide Cetylpyridinium
chloride

15. Non-ionic surfactants
• Those surfactants do not have any electrical charge, which
makes them resistant to water hardness deactivation.
• The hydrophilic part contains the polyoxyethylene,
polyoxypropylene or polyol derivatives.
• The hydrophobic part contains saturated or unsaturated
fatty acids or fatty alcohols they are excellent grease/oil
removers and emulsifiers.
• Non-ionic surfactants contribute to making the surfactant
system less hardness sensitive.
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Tween 40

16. The non-ionic surfactant can be classified as
• 1. ETHOXYLATED ALCOHOLS AND ALKYLPHENOLS general formula
RXH, that can ionize as RX-. e.g., : Ethoxylated Linear Alcohols, Ethoxylated
Alkyl Phenols, Cetyl Alcohol, oleth-20 , steareth-2(Brij )
• 2. FATTY ACID ESTERS e.g., : Glycerol monostearate , PEG-100 glyceryl
stearate (commecial name : Simulsol), sorbitan esters (comercial name : Span,
Tween)
• 3. NITROGENATED NONIONIC SURFACTANTS e.g., ; Tertiary amine oxides,
ethoxylated imide.
The most commonly used non-ionic surfactants are ethers of fatty acids.
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18. Amphoteric/Zwitterionic surfactants
• These surfactants are very mild, making them particularly suited for use in
personal care preparations over sensitive skins.
• They can be anionic (negatively charged), cationic (positively charged) or
non-ionic (no charge) in solution, depending on the acidity or pH of the water.
• Those surfactants may contain two charged groups of different sign.
• Whereas the positive charge is almost always ammonium but the source of the
negative charge may vary (carboxylate, sulphate,sulphonate).
• These surfactants have excellent dermatological properties.
• They are frequently used in shampoos and other cosmetic products, and also
in hand dishwashing liquids because of their high foaming properties
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19. • 1. AMINO PROPIONIC ACIDS: Their isoelectric point is around pH = 4. They
adsorb on skin, hair, and textile fibers. The dodecyl amino propionic acid is used
in cosmetics as wetting agent and bactericide.
• 2. IMIDO PROPIONIC ACIDS :Their isoelectric point is around pH = 2-3. They
are used as textile softeners. Dicarboxylic compounds of alkyl imidazole are used
in cosmetics and de luxe soap bars.
• 3. QUATERNIZED COMPOUNDS :Quaternized compound have similar
structures. The most important are betaines and sulfobetaines or taurines.
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Dodecyl amino propionic acid

20. Polymeric surfactants
• These surfactants have many uses, in particular as colloid and nanoemulsion
dispersants, wetting agents, detergents. There are two main configurations:
"block" and "graft“, where H and L represent hydrophilic and lipophilic monomer
units.
• The result is a macromolecular surfactant. Although the hydrophilic and lipophilic
parts are quite separated, the polymer polarity segregation is not that obvious since
both groups are slightly polar.
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21. Examples :
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Ammonium acryloyldimethyltaurate/VP
(Aristoflex ® AVC) copolymer
Carboxy Methyl cellulose (CMC)

22. Silicone surfactants
• Silicone surfactants—copolymers of silicone and
polyethers—are useful for applications in which
their high surface activity .
• They have recently been shown to enhance the
efficiency of micro emulsions.
• Silicone surfactants have ability to reduce the
surface tension of polar and non-polar liquids to
values 15–20 mN/m lower than commonly
achieved with organic-based surfactants.
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Dimethicone copolyol

23. • Common examples are PEG/PPG-18/18 dimethicone, bis-PEG/PPG-14/14
dimethicone and cetyl PEG/PPG-10/1 dimethicone.
• Dimethicones remain important for their emollient properties and their ability to
improve the skin feel of many types of skin care formulations.
• Cyclomethicones are volatile, low-viscosity silicone fluids that act as cosmetic
solvents
• Silicone fluids are widely used in sunscreen formulations because of their ability to
reduce the oily and sticky skin feel associated with high levels of organic sunscreen
oils.
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APPLICATIONS OF SURFACTANTS IN
COSMECEAUTICALS

27. Surfactants are useful for the following application:
1. Cleansing
2. Emulsification
3. Solubilization
4. Conditioning
5. Foaming
6. Special effect
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28. Cleansing
• The useful thing about micelles is that they can help suspend oil in water. when
you put a surfactant solution on a surface like hair or skin, the oil that is there will
be drawn away from the surface and into the micelles.
• When the surfactant solution is rinsed away, the surface is cleansed.
Foaming
• Foam is another characteristic of surfactant solutions so you’ll need surfactants if
you want your product to foam.
• It should be noted that foam itself is not related to the ability of a product to clean.
• Decyl glucoside is the best in terms of foaming as it creates a rich and dense foam.
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29. Emulsification
• While cleansing cosmetics remove oils, many cosmetic products are design to add
oily materials to the skin and hair.
• These ingredients usually can’t be applied directly. For this reason, cosmetic
chemists create emulsions using surfactants.
• A surfactant, or emulsifier, is used to help blend and stabilize the mixtures.
• In the simplest case, an emulsion formula is made by mixing an oil phase with a
water phase and a surfactant.
• The micelles created by the surfactant entrap the oil in their centers and it remains
suspended throughout the mixture.
• Products like creams and lotions are typically emulsions.
• When the product is applied to the skin or hair, the surfactant micelles break open
and deliver theoily materials.
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30. Solubilization
• The problem with most emulsions is that they usually create opaque products.
• There are surfactants that have the ability to create particles so small that light
passes through them and the solutions remain clear.
• Molecules that do this are solubilizing surfactants.
• They are used to blend oily materials like fragrances or natural ingredients into
clear solutions.
• An example would be a surfactant like Polysorbate 20.
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31. Conditioning
• Since surfactants often contain an “oily” part on their molecule, they have
conditioning properties that can improve the feel and look of the surfaces of skin
and hair.
• For them to work this way, the surfactants have to be left behind and also be non-
irritating.
• This can be achieved through a leave-on cosmetic product or by using surfactants
that can bond to surfaces through an electrostatic charge.
Special effects
• For example, some surfactants have anti-microbial effects so they can be used as a
preservative.
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