Cosmetic excipients used in the preparation of various skin care, hair care and oral care formulations.

1. Cosmetic Excipients: Surfactants
Dhanshri O. Tikekar, Dipti A. Fating
Subject: Cosmetic Science,
B. pharm final year
Guide name: Chandrashekhar M. Chakole
Bajiraoji Karanjekar College of Pharmacy, Sakoli,
Dist: Bhandara. M.S.-441802
Rashtrasant Tukadoji Maharaj Nagpur University

2. Contents
1. What is surfactant?
2. Structure of surfactants
3. Mechanism of action of surfactants
4. Tyes of surfactants
5. Properties of surfactants
6. Applications of surfactants
7. Reference

3. 1) What is surfactant?
The term “surfactant” was coined by Antara Products in
1950.
Surfactants (Surface active agents) are compounds
which help to decrease the surface tension between
two liquids, a liquid and a gas or a liquid and a solid.
Surfactants allow easier spreading and dispersion and
as well as lower the interfacial tension between two
liquids.
Surfactant’ is the official name for surface-active
agents. The substitute word ‘tensides’ is derived from
the Latin word ‘tensus’, which has the meaning ‘tense’
in English.

4. 2) Structure of surfactant:
 The surfactant molecules are characterized by having two groups
in their molecular structure.
 Hydrophilic head and hydrophobic tail both are important
determinants of lowering surface tension.
 The hydrophilic group (water-attracting group)has an affinity for
water and have strong affinity for solvents. They can be neutral or
charged.
 Hydrophobic group (water repelling group) such as hydrocarbon
chain that has no affinity for aqueous solvents.

5. 3) Mechanisms of action of surfactant:
There are three mechanisms of action of surfactants, and they are as follows:
1. Roll-up mechanism: Adam in 1937, first proposed the roll-up mechanism. To remove the
oil droplets from a rock surface the roll-up mechanism is a good way. When the contact
angle is between the aqueous phase and the substrate decreases, the roll-up mechanism
occurs.
2. Emulsification: The surface-active agents reduce the interfacial tension between oil and
water and make the emulsification of oil and water.
3. Solubilization: In this mechanism, through interaction with the micelles of surfactant in
the aqueous phase(water), the substance gets dissolved to form a stable solution without
having any impurity. The micelles work as a unit to remove the dirt. The hydrophobic tails
get attracted towards soils and surround them; on the other hand, the hydrophilic heads
pull the surrounded soils from the surface into the solution.

6. 4) Types of surfactants:
Surfactants are classified based on their polar head. The hydrophilic head
of the surfactants has a charge with some kind of charge. The charges can
be negative(anionic), positive(cationic), or neutral. Some surfactant consists
of two opposite charges.
1) If the head of the surfactant carries a positive charge, then it is
classified as a cationic surfactant.
2) If the surfactant head carries a negative charge, then it is classified as
anionic surfactant.
3) If the surfactant head does not carry any kind of charge, then it is
called a non-ionic surfactant.
4) If the surfactant carries both negative and positive charge, then it is
classified as amphoteric surfactant.

7. Cationic surfactants
 Cationic surfactants are agents which are composed of polar and non-polar
parts. The polar part of these agents is always composed of a quaternary
ammonium unit.
 Cationic surfactants are ineffective as detergents in cleansing systems because
they bear positively charged groups on their polar head.
 These positively charged surfactants are primarily used in conditioners.
Cationic surfactants are well known for their conditioning effect as these
surfactants bond to the negatively charged hairs.
 Examples are benzalkonium chloride, methylpyridinium chloride, cetrimide
stearyl alkonium chloride, etc.

8. Anionic surfactants
Anionic surfactants are organic substances. When these surfactants are dissolved in
water, they produce negatively charged particles, called anions.
 Anionic surfactants are strong cleaners. They are excellent at removing sebum and
dirt.
Anionic surfactants can be produced from a variety of raw fats and oils, including
soybean, tallow, palm and coconut.
Examples are Sodium lauryl sulphate, sodium lauryl ether sulphate, sodium cocoyl
sulphate, and ammonium lauryl sulphate.

9. Non-ionic surfactants
 Non-ionic surface-active agents are neutral in nature as they do not have any
kind of charge on their hydrophilic head.
 These surfactant refers to the molecules which do not undergo ionization when
dissolved in water.
 These surfactants are gentler than anionic surfactants and are very good at
emulsifying oils and better at removing organic soils.
 Certain non-ionic surfactants are non-foaming or low-foaming which makes
them a good choice as low-foaming detergent.
 Examples are Cetyl alcohol, stearyl alcohol, cetostearyl alcohol, lauryl
glucoside, glyceryl laurate, polysorbates, spans, and Poloxamers.

10. Amphoteric surfactants
 These are the surfactants which consists dual charges i.e. both positive and
negative charges on their hydrophilic end. These dual charges cancel each
other hence the net charge is zero. This is known as zwitterion.
 The amphoteric surfactants become positively charged and behaves like
cationic surfactants in acidic solution while in alkaline solution they become
negatively charged and behave like anionic surfactants.
 The characteristics of amphoteric surfactants are better emulsification and
dispersion, excellent smoothness and softness, acts as an antistatic agent to
the fabrics, etc.
 Examples are
 Cocamidopropyl
betaine, sodium cocoamphoacetate, alkylamidopropylamine N-
oxide(APAO).

11. 5) Properties of surfactants:
 Decreasing surface tension: Surfactants have the good property of lowering surface tension between two liquids
or between a solid and a liquid. This property allows the surfactants to penetrate through the surface and spread
evenly on the surface. It allows the proper mixing of various types of molecules.
 Dispersing: In this phenomenon, the non-polar substances form the tiny particles in water and get evenly
dispersed. Surfactants enhance the dispersion process. The efficiency of the dispersion process is mediated by the
surfactant’s interaction with the material and the structural features of the surfactants like the charge of the polar
group and its type, and length of the alkyl chain.
 Softening: Surfactants have good softening properties. The surfactants having excellent softening effects are
preferably used as a conditioning agent in shampoo and conditioners. Mon alkyl and dialkyl quaternary ammonium
salts, and alkylbenzyl quaternary ammonium salts are most commonly used in cosmetic preparation.

12.  Cloud point: Cloud point is also called a lower consolute temperature. It refers to the phase
transfer of non-ionic surfactants. In this phase transfer
system, the clear homogeneous solution is converted into a cloudy solution.
 Micellization: It is the dynamic process in which monomeric surfactant molecules aggregate
into a discrete structure. The concentration at which micelles appear at the given temperature
is known as critical micelle concentration.
 Wetting and penetrating: Surfactants reduce the cohesion between the water molecules and
penetrate through them. This process lowers the energy difference between the water and the
pigment and also reduces the surface tension. Surfactants with good wetting and penetrating
properties spread evenly and can enhance the cleaning, dispersion and emulsification
process.

13. 6) Applications of surfactants:
 Surfactants in hair care: Detergency of surfactants id depends on the length of
hydrocarbons. Shorter chain-length surfactants have stronger grease-removing
properties. Long-chain surfactants improve mildness and reduce lathering
properties.
 Shampoo: Shampoo is the widely used hair care preparation in the market of
hair cosmetics. Surfactants in shampoo formulations form micelles and wash out
the dirt and oil from the hairs. Anionic surfactants are generally used in
shampoos they provide lather and detergency to the shampoo.
 Conditioners: Conditioning surfactants are the opposite of shampoo
surfactants as they deposit on the hair. In hair conditioners, cationic surfactants
are mainly used as they are positively charged. These surfactants are meant to
adsorb on the shaft of the hairs rather than being washed off.

14.  Surfactants in makeup and skincare: Surfactants are an important part of the
skincare and makeup industry. In skincare products, surfactants are used as
emulsifiers for the formulation of different creams, lotions body washes, etc.
 Lotions and creams: lotions and creams are applied to soften, smooth and
moisturize the skin. Polyethylene glycols are essentially used as the base for
creams and lotions. PEGs are compounds which are used as thickeners,
solvents, and softeners also they are good at carrying moisture.
 Body washes: surfactants are the essential components in body washes.
Surfactant’s job is to clean the skin by removing hydrophilic dirt and
naturally produced oils from the body. Surfactants act as the cleansing agent
in the body- washes as they pull off oil-based dirt and microbial
contaminants from the body.

15. Surfactants used in oral hygiene:
Surfactants are commonly used in oral hygiene formulations like
mouthwashes, and kinds of toothpaste. In oral hygiene products they act as
solubilizing, wetting and dispersing agents and give the foaming effect.
Toothpaste: surfactants reduce the surface tension of the watery
environment of the oral cavity so the toothpaste can contact easily with the
teeth. They help to loosen the debris and plaque and make the cleaning
process easier.
 Mouthwashes: Mouthwashes used for cosmetic purposes are prepared to
reduce bad breath with the help of flavouring and antimicrobial agents.
Surface active agents are used in the mouthwashes because they help in the
solubilization of all the flavours and remove the debris by producing
foaming action.

16. Conclusion
 Surfactants play a vital role in various cosmetic and personal care products due to their unique
properties. Their ability to lower surface tension, emulsify, solubilize, disperse, and wet surfaces makes
them indispensable ingredients in formulations like shampoos, conditioners, creams, lotions, body
washes, kinds of toothpaste, and mouthwashes.
 The different types of surfactants - anionic, cationic, non-ionic, and amphoteric - offer specific
functionalities tailored for different applications. Anionic surfactants provide excellent cleansing and
foaming action, while cationic surfactants impart conditioning effects on hair. Non-ionic surfactants are
mild and effective emulsifiers, and amphoteric surfactants offer versatility by behaving as either anionic
or cationic depending on the pH.
 The choice of surfactant and its concentration in a formulation significantly impacts the product's
performance, mildness, and sensory attributes. Careful selection and blending of surfactants are crucial in
creating effective and consumer-pleasing cosmetic products. As cosmetic science continues to evolve,
surfactants will remain essential ingredients, driving innovation and meeting the ever-changing consumer
demands for high-performance and multifunctional cosmetic products.

17. 7) References
1. Wilkinson, Moore, (1982), Harry’s Cosmeticology, Seventh edition, Chemical Publishing, USA. P-633-640.
2. Sharma P.P. , (2014), Cosmetics – Formulation, Manufacturing and Quality Control, Fifth edition, Vandana
Publication Pvt. Ltd., Delhi. P-94-103.
3. Pathak . K., and Vaidya A., (2018), A textbook of cosmetic science concepts and principles, First edition, Nirali
Publication, Pune. P- 3.1- 3.4.
4. Singh S.P., and Nigam V., (2021), Cosmetic Science textbook, First edition, Thakur Publications Pvt. Ltd.
Lucknow. P-22-23.
5. Mehetre G.D., Ambhore J.P., Cheke R.S., Shinde S.D., (2022),Cosmetic Science, First edition, S. Vikas and
Company (medical publishers), Jalandhar. P-9-22.

18. Thank You