Formulation building blocks;
surfactants , EMOLLIENTS AND
RHEOLOGICAL ADDITIVES
1
www.DuloMix.com
CONTENTS
1. FORMULATION BUILDING BLOCKS.
2. SURFACTANTS.
3. RHEOLOGICAL ADDITIVES.
4. EMOLLIENTS.
5. REFERENCES.
2
www.DuloMix.com
FORMULATION BUILDING BLOCKS
➢The number of compounds produced, exceeds the number
of chemical steps required to make them.
➢A chosen set of building blocks are reacted together to
make every available product and collection of these
product is referred as “library” or an “array”.
➢This is collection of compounds can be synthesized as
mixture of individuals using variety of techniques.
3
www.DuloMix.com
SURFACTANTS
Surfactants are surface active agents widely used in
cosmetics products specially in Shampoos, Dentifrices, etc.
these compounds are characterized by foam production and
reduction of surface or interfacial tension.
➢ These are materials which have tendency to preferentially
get absorbed at the interface between two phases.
➢ They are Amphiphilic in nature, and comprises of both a
Lipophilic and Hydrophilic component.
➢ Polar- high polarity
➢ Non polar- low polarity
4
www.DuloMix.com
➢ These surfactants are generally given a name, based on
nomenclature adopted by CTFA cosmetics ingredients
dictionary.
➢ Four types basis on the electric charge carried on the
hydrophobic portion of the Amphiphile.
They are
1. Amphoteric
2. Anionic
3. Cationic
4. Non-ionic
5
www.DuloMix.com
1. Amphoteric surfactants
➢ Acyl-Amino acids and derivatives
➢ N- Alkyl Amino Acids
2. Anionic surfactants
➢ Acyl amino acids and salts
i. Acyl glutamates
ii. Acyl peptides
iii. Sarcosinates
iv. Taurates
➢ Carboxylic acids and salts
i. Alkonic acids
ii. Ester carboxylic acids
iii. Ether carboxylic acids
6
www.DuloMix.com
➢ Phosphoric acid esters and salts
➢ Sulfonic acid and salts
i. Acyl istheonates
ii. Alkyl aryl sulphonates
iii. Alkyl sulphonates
iv. Sulfosuccinates
➢ Sulfuric acid esters
i. Alkyl ether sulfates
ii. Alkyl sulfates
3. Cationic surfactants
➢Alkylamines
➢Alkyl imidazolines
➢Ethoxylated amines
7
www.DuloMix.com
➢Quaternaries(QAC)
i. Alkylbenzyldimethyl ammonium salts
ii. Alkyl betaines
iii. Heterocyclic ammonium salts
iv. Tetra alkyl ammonium salts
4. Non ionic surfactants
➢Alcohols
➢Alkanolamides
i. Alkanolamine derived amides
ii. Ethoxylated amides
➢Amine oxides
8
www.DuloMix.com
➢Esters
i. Ethoxylated carboxylic acids
ii. Ethoxylated glycerides
iii. Glycol esters
iv. Monoglycerides
v. Polyglyceryl esters
vi. Polyhydric alcohol esters and ethers
vii. Sorbitan/ sorbital esters
viii. Triesters of phosphoric acid
➢Ethers
i. Ethoxylated alcohol
ii. Ethoxylated lanolin
iii. Ethoxylated polysiloxanes
iv. Propoxylated POE esters
9
www.DuloMix.com
1.AMPHOTERIC SURFACTANTS
➢Amphoteric- charge on the hydrophobe changes as a
function of the pH .
➢They carry a
-Cationic charge in strongly acidic media
-Anionic charge in strongly basic media
-forms zwitterionic species at intermediate pH
Two types:
a. Acyl / Dialkyl ethylene diamine and Derivatives
b. N- Alkylmino acids
10
www.DuloMix.com
a. Acyl / dialkyl ethylene diamine and derivatives
Chemical properties:
➢They are heterocyclic derivatives of imidazolines.
➢They are not pure chemical entities but contains various
compounds formed during their synthesis.
➢Impurities makes its Amphoteric nature- Zwitter ionic
compound in the neutral pH range.
Principle impurities: Acylamphoacetate, Acylamphodi
Propionate, Acylamphohydroxypropylsulfonate, Acylampho
Diacetate, Acylamphopropionate.
Physical properties:
➢These surfactants are commonly distributes as aqueous
solutions or pastes.
11
www.DuloMix.com
Uses:
➢These are mild detergents but relatively poor emulsifiers.
➢They compatible with all other surfactants and it can
tolerate hard water.
➢Used in shampoo- they do not interfere with foaming
production and later reduce tendency to produce eye
irritation.
Stability:
➢The amido group that may be hydrolyzed at extreme pH
conditions – may be considerable stable.
Safety:
➢At normal concentration –well tolerated by skin and
mucous membranes.
➢Cause eye irritation at milder concentration.
12
www.DuloMix.com
b. N-Alkylamino acids
Chemical properties:
➢They derived from various amino acids and its members do
not possess the hydroxyethyl group.
➢They are the alkyl derivative of β-alamine or of β-N ( 2-
carboxyethyl) alamine.
➢On fully neutralized solution- behaves as amines.
➢On pH 6- exhibit their zwitterionic character.
Physical properties:
➢They available as solids also distributed in solution form.
Uses:
➢On the neutral/ alkaline pH- copious foam.
➢At low pH-lose their foaming power(behaves as cation).
➢Zwitterionic forms- all types of hair products.
13
www.DuloMix.com
2. ANIONIC SURFACTANTS
➢ Charge on the hydrophobe is negative.
➢ No charge on the hydrophobe unless it elevated the pH to
neutral or above are categorized as anionic
➢ Eg. Carboxylic acids.
Four types:
1. Acylamino acids and salts.
2. Carboxylic acids and salts.
3. Sulfonic acids and salts.
4. Sulfuric acids esters.
14
www.DuloMix.com
a. Acyl amino acids and salts
➢ Prepared by the acylation of amino group of α-amino
acids.
➢ This is conducted primarily with naturally occurring fatty
acids.
➢ During the acylation, neutralization of amino group of
amino acid – anionic surfactants.
Sub divided into four types
i. Acylglutamates.
ii. Acylpeptides.
iii. Sarcosinates.
iv. Taurates.
15
www.DuloMix.com
Physical Properties:
➢ Solids, 30% Marketed as solution, Alcoholic solution,
Pastes and Water soluble salts.
Uses:
➢ Skin Cleansing Products, Shampoos and Bubble Baths.
Stability:
➢It possess adequate resistance to hydrolysis.
➢Acyl peptides can support microbial growth, because
they have a tendency to inactivate some preservatives.
Safety:
➢Non irritating and non sensitizing, reduced tendency to
defeat the skin.
16
www.DuloMix.com
b. Carboxylic acids and its salts
➢ Carboxylic acids are the organic compounds that possess
the COOH function.
➢ They are weak acids and their water solubility depends on
their neutralization, with suitable alkali.
➢ As a group they are primarily compatible with anionic and
nonionic surfactants.
Three groups:
i. Alkanoic acids
ii. Ester carboxylates
iii. Ether carboxylates
17
www.DuloMix.com
Physical properties:
➢Solids, Soft and Hard waxy solids, Aqueous suspension
and Solution.
Stability:
➢Alkanoic acids are not chemically altered by exposure to
acids or alkalis.
➢It may detoriated due to some oxidative reactions.
➢It cause rancidity and yellowing of the unsaturated
members of this class.
Safety:
➢The salts with alkali metals of alkanoic acids are cause
irritation.
Uses:
➢Deodorant Stick Products, Conventional Salt Bars,
Shaving Preparations and Shampoos.
18
www.DuloMix.com
c. Phosphoric acid esters and its salts
➢They are the Mono and Di-esters of phosphoric acid and
their salts.
➢The Di-esters are more Lipophilic than the Monoesters.
Physical properties:
➢Solids, tacky viscous fluids.
Stability:
➢They readily hydrolyzed in acidic media.
➢Exhibit acceptable stability in neutral and alkaline pH.
Uses:
➢Emulsifiers and solubilizing agents in micro emulsion.
19
www.DuloMix.com
d. Sulfonic acids
➢ They chemically contains stable C-S bond.
➢ They used only in the form of salts.
Four groups:
i. Acyl istheonates
ii. Alkylaryl sulfonates
iii. Aryl sulfonates
iv. Sulfosuccinates
Physical properties:
➢ Powders, flakes, aqueous solution.
➢ They foam well and exhibit good detergent properties.
Stability:
➢Acyl istheonates- may undergo hydrolysis at extreme pH.
Uses:
➢Shampoos, Skin cleansing agents, Bubble bath.
20
www.DuloMix.com
d. Sulfuric acid esters
➢ They are the salts of monoesters of sulfuric acid.
➢ The free acids are not available commercially.
Two types:
i. Alkyl ether sulfates
ii. Alkyl sulfates
Physical properties:
➢Aqueous solution and pastes.
Stability:
➢They hydrolysis at extreme pH.
Safety:
➢Alkyl sulfates irritating at higher concentration.
➢They also believed to defat epidermal tissues.
21
www.DuloMix.com
3. CATIONIC SURFACTANTS
➢ Charge on the hydrophobe is positive charge.
➢ Substance in which the hydrophobe carries no charge, unless
the pH is lowered close to neutrality or lower.
Four types:
a. Alkylamines
b. Alkyl imidazolines
c. Ethoxylated amines
d. Quaternaries
22
www.DuloMix.com
a. Alkylamines
➢They form a fairly large group of cosmetic surfactants.
Two types:
➢Simple alkylamines and their salts.
➢Ethoxylated amines.
Amino function is responsible for the surface active
properties and the water solubility of alkylamines
compounds.
Physical properties:
➢Waxy solids.
Stability:
➢They chemically stable.
➢They hydrolysis under the extreme pH.
Uses:
➢Hair conditioners and shampoos.
23
www.DuloMix.com
b. Alkyl imidazolines
➢It comprise a small group of basic heterocyclic substances.
➢They obtained by the reaction of amino ethylethanolamine
with suitable fatty acid.
Physical properties:
➢Liquids and aqueous solution.
Stability:
➢Imidazolines are subject to hydrolysis to the amide, and
reformation of the cyclic structure is probably pH
dependent.
Safety:
➢Irritating unless they are neutralized with suitable acid.
Uses:
➢They employed in the aqueous media, emulsifiers or as
substantive hair conditioning agents
24
www.DuloMix.com
c. Ethoxylated amines
➢They are the group of nitrogen containing surfactants.
➢They relatively weak bases and do not require large amount
of acids to adjust their pH to the range normally used in the
cosmetics.
Physical properties:
➢Waxy solids
Stability:
➢These are acid and alkali stable and are not subject to the
hydrolysis.
Uses:
➢Emulsifying agents, hair conditioning agents.
25
www.DuloMix.com
d. Quaternaries
➢They comprise a large number of surfactants and
antimicrobial agents.
➢Positive charge is retained in the environmental pH.
Four classes:
i. Alkyl benzyl dimethyl ammonium salts
ii. Betaines
iii. Heterocyclic ammonium salts
iv. Tetra alkyl ammonium salts.
Safety:
➢It causing ocular and topical irritation, although their
potential for skin penetration is quite low.
26
www.DuloMix.com
i. Alkyl benzyl dimethyl ammonium salts
➢These are formed by the alkylation of alkyldimethylamines
with benzyl chloride.
➢These substance are not compatible with anionic surfactants.
Physical properties:
➢Solids, aqueous suspension or solution.
Stability:
➢Quaternaries form the less stable hydroxides in the very
pH range, but these conditions are unlikely to occur in
cosmetic use.
Safety:
➢Causing ocular and topical irritation, although their
potential for skin penetration is quite low.
Uses:
➢Hair conditioning agents, skin degerming agents and
deodorants, used in creams and lotion. 27
www.DuloMix.com
ii. Alkyl betaines (and related compounds)
➢These are N-alkyl derivatives of N-dimethyl glycine.
➢The simple alkyl betaines may be viewed as the derivatives
of N-dimethyl alkylamines formed by alkylation with
chloroacetic acid.
➢In acid solutions- exist as positively charged cations.
➢In alkaline solution- they carries both positive and negative
charge.
➢At intermediate pH(4-8)-may exist partially as zwitterions.
➢At near isoelectric point and depending on concentration-
may form complexes with anionics that may interact with a
product performance.
28
www.DuloMix.com
Physical properties:
➢Solids, solutions; they foam well even in hard water.
Stability:
➢They exhibit good stability.
Safety:
➢They exhibit low eye and skin irritation potential.
Uses:
➢Provide excellent conditioning agents and antistatic
properties,
➢Used in shampoos, facial cleansing agents, rarely used as
emulsifiers.
29
www.DuloMix.com
iii. Heterocyclic quaternaries
➢They derived from heterocyclic aliphatic or aromatic
compounds in which a ring nitrogen atom is quaternized.
➢The original heterocyclic nitrogen atom may be part of
morpholine, imidazoline, pyridine or iso-quinoline derived
quaternaries.
➢It may subject to hydrolysis.
Physical properties:
➢They are water soluble solids.
Stability:
➢They exhibit good stability.
Uses:
➢Hair conditioning agents, Antistatic agents and
Antimicrobial agents.
30
www.DuloMix.com
iv. Tetra alkyl ammonium salts
➢They posses four alkyl groups and it represented as anion.
➢The solubility of these quaternaries depends on the nature of
the substituent alkyl groupings.
➢More polar members- water soluble.
➢Less polar members- oil soluble.
Physical properties:
➢Solids, solutions or aqueous pastes.
Stability:
➢They exhibit considerable stability.
Uses:
➢Hair and skin conditioners, Antistatics, Antimicrobials,
Emulsifiers.
31
www.DuloMix.com
4. NON IONIC SURFACTANTS
➢ If the hydrophobe carries no charge at the pH at which the
Amphiphile is normally used in cosmetic products.
➢ Ethoxylation is common characteristics of many non ionic
surfactants.
➢Many non-ionics could be classified as alcohols and ethers.
Five types:
a. Alcohols
b. Alkanol amides
c. Amine oxides
d. Esters
e. Ethers
32
www.DuloMix.com
a. Alcohols
➢They are the hydroxyl derivatives of long chain alkane
hydrocarbons.
➢They exhibit classic surface and interfacial alignment
behaviour of surfactants.
➢Water insolubility is the reason for their inclusion only as co-
emulsifiers.
➢Only primary alcohol having carbon chain ranging from 8-
18-useful surfactant properties.
➢Surfactant alcohols were initially obtained by hydrogenation
of the corresponding natural fatty acids.
➢Zieglar-even numbered straight chain alcohols.
➢Oxo-even and odd numbered alcohols.
33
www.DuloMix.com
Physical properties:
➢Waxy solids, liquids.
➢Tend to crystallize in finished emulsion unless they are
carefully formulated.
Stability:
➢Stable in cosmetic products.
Safety:
➢They regarded as safe for use in cosmetics.
Uses:
➢Emulsion stabilizers, opacifiers, viscosity modifiers,
foam boosters and co-emulsifier.
34
www.DuloMix.com
b. Alkanolamides
➢They are the diverse group of compounds, all of which contain
at least one alkyl or POE grouping.
➢Ethoxylated amides-water insoluble- depends on the size and
number of POE substituent.
➢Alkanolamine-water insoluble-pure form of alkanoic acid.
Two types:
i. Alkanolamine derived amides.
ii. Ethoxylated amides.
Physical properties:
➢Waxy/soft solids; colour varies widely.
➢Ethoxylated amides- do not foam well
35
www.DuloMix.com
Stability:
➢Alkanolamides- Hydrolysis at extreme pH, although tend
to colour on exposure to light and air.
Safety:
➢Alkanolamine contains free Diethanolamine-form a
carcinogenic nitroso compound by an unknown mechanism.
Uses:
➢Foam boosters, viscosity increaser in shampoos,
antiperspirants, acidic permanent wave neutralizers, lime
soap dispersants and emulsifiers at low pH.
36
www.DuloMix.com
c. Amine oxides
➢These are prepared by the hydrogen peroxide oxidation of
tertiary aliphatic amines.
➢They may be linear or cyclic.
Physical properties:
➢30-50% as aqueous solution or dispersions.
Stability:
➢Have a acceptable stability in cosmetics.
Safety:
➢They evidently are well tolerated in cosmetics as long as
free hydrogen peroxide or neutralized amines are absent.
Uses:
➢Antistatics, Hair conditioning agents, foam boosters in
shampoos, lime soap dispersants
37
www.DuloMix.com
d. Esters
➢Most of the esters are alkaoic acids, formed by reaction with
ethylene oxide, glycerin or sorbitan.
➢Their use is generally restricted to pH ranges from about 5-9.
➢An additional level of instability-unsaturated acids form part
of the molecule because oxidative attack may affect the odour
or colour of a product.
Subdivided into eight groups:
i. Ethoxylated carboxylic acids.
ii. Ethoxylated glycerides.
iii. Glycol esters and derivatives.
iv. Mono glycerides.
v. Poly glyceryl esters.
vi. Polyhydric alcohol esters and ethers.
vii. Sorbitan/sorbital esters.
viii. Tri esters of phosphoric acid.
38
www.DuloMix.com
Physical properties:
➢Mobile liquids/ fairly hard solids, waxy solids, coloured
viscous tacky liquids and viscous fluids.
Stability:
➢Mono glycerides, polyhydric alcohol esters and ethers-
cannot be used in products at extreme pH ranges.
Safety:
➢The majority of the member of this class have long history
of safe use in cosmetics, some of them are used in food
products.
Uses:
➢Emulsifying agents, solublizing agents, suspending agents,
skin conditioners or emollients, mild surfactants in
shampoos and they are used in creams and lotions.
39
www.DuloMix.com
e. Ethers
➢Ethers are distributed widely among cosmetic surfactants.
➢They are mostly ethoxylated and propoxylated derivatives.
Sub divided into four subgroups:
i. Ethoxylated alcohols.
ii. Ethoxylated lanolin.
iii. Ethoxylated polysiloxane
iv. Propoxylated POE ethers.
Physical properties:
➢Fairly mobile liquids or rather hard solids(depending on
the ethoxylation), colorless liquids and of solids.
➢Ethoxylated lanolin- beige colored waxy solids.
40
www.DuloMix.com
Stability:
➢They exhibit acceptable stability in cosmetics as well as
food stuffs.
Safety:
➢Ether derivatives are considered safe for cosmetic use.
➢Several of them can be used in food stuffs and some of
them have been used in drug application on open wounds.
Uses:
➢Emulsifier, effective detergents, suspending agents,
solublizers, spreading agents, lime soap dispersants and in
skin care products.
41
www.DuloMix.com
RHEOLOGICAL ADDITIVES
➢The term Rheology derived from two Greek words namely
rheo (to flow) and logos (science).
➢Rheology is the science that deals with the deformation of
matter under the influence of stresses like tensile stress,
shearing stress, etc.,
➢It deals with the fluids flow.
➢Rheological additives generally focused to “Thickeners”.
➢Product rheology has direct impact on stability, whether it
due to viscosity control, emulsion stability, suspension actives
or prevention of syneresis.
➢Their primary roles in flow behavior may include
detergency, emulsification, foam stability or conditioning.
42
www.DuloMix.com
Classification of Rheological Additives
➢They have been categorized by general class and their origin
or source. The general classes are described as follows;
1. Natural gums: Harvested directly or derived from natural
plant, microbial or animal source.
2. Modified naturals: Synthetic derivatives of natural gums.
Also classified as semi synthetics.
3. Synthetics: Polymers synthesized from petroleum or
other hydrocarbon based raw materials.
4. Inorganics: Inorganic mineral derived. Either refined,
naturally occurring ores or synthetically produced.
43
www.DuloMix.com
Classification of Gums, Thickeners and Polymers
I. Natural gums
A. Plant source:
i. Trees and shrub exudates- Karaya Gum,
Tragacanth Gum, Gum arabic, Gum ghatti.
ii. Seed extracts- Guar Gum, Locust Bean Gum,
Quince seed, Psyllium seed, Tamarind seed.
iii. Seaweed extracts- Carrageenan, Alginates, Agar.
iv. Tree extracts- Larch Gum.
v. Fruit Extracts- Pectins.
vi. Grains and Roots- starches.
B. Microbial:
Exocellular polysaccharides- Xanthan Gum, Dextran.
44
www.DuloMix.com
C. Animal:
i. Milk Proteins- Casein.
ii. Skin Bones- Gelatin, Keratin.
iii. Insect secretion- Shellac.
II. Modified natural
Plant:
i. Wood Pulp and Cotton- Cellulose Derivatives.
ii. Seed extracts- Guar Derivatives.
III. Synthetics
i. Petroleum based- Acrylic polymers,
Polyacrylamides, Alkylene/ Alkylene Oxide
polymers.
IV. Inorganics
i. Clays- Smectite Hydrophilic and Organoclays.
ii. Amorphous Silicon Dioxide- Hydrated silica,
Fumed silica. 45
www.DuloMix.com
➢The majority of the monosaccharide’s residues found in the
natural thickeners are six membered rings.
➢These rings consists of five carbon atoms and one oxygen
atom, are classified as pyranose group or the pyrans.
➢Most monosaccharide found in the natural thickeners are
aldohexoses or the hexuronic acids.
Aldohexoses: a six carbon monosaccharide containing an
aldehyde group.
➢There are 16 possible aldohexoses, considering
stereoisomers.
Hexuronic acids: similar to the aldohexoses but with a
carboxylic acid group occurring at c-6 of the ring structures.
46
www.DuloMix.com
Aldohexoses
Monosaccharide Natural polymer containing
D-glucose Cellulose based gums, Xanthan gum
D-mannose Guar gum, Locust bean gum, Xanthan gum
D-galactose Carrageenan, Guar gum, locust bean gun.
3,6-anhydro D-galactose carrageenan
Hexuronic acids
Monosaccharide Natural polymer containig
D-glucuronic acid Xanthan gum
D-mannuronic acid Alginates
D-galactouronic acid Karaya gum
L-guluronic acid Alginates
47
www.DuloMix.com
Plant origin Natural Polymers
1.Tree/Shrub Exudates
a. Karaya Gum:
➢High molecular weight, partially acetylated
polysaccharide.
➢Exudates of Sterculia urens tree, found primarily in
India. Also Known as Sterculia gum. Least water soluble
of the commercial exudates.
Solution properties:
➢Poor water solubility; particles from swollen gels.
➢Forms viscous aqueous mucilage that are best when gum
is fresh.
➢Gum is subjected to significant viscosity loss when it is
stored in purified form
48
www.DuloMix.com
➢The most important property is that an exceptional
mucoadhesive is formed with a small amount of water.
➢For this reason, karaya is used in denture adhesives.
➢Earlier powdered denture adhesive formulations contained
upto 90% karaya gum.
Rheology:
➢Sols are non-Newtonian, thixotropic, and thermally
reversible.
➢At pH less than 7, sols have a short texture.
➢At pH 7 or higher, sols form a ropy mucilage, due to
irreversibile de-acetylation.
49
www.DuloMix.com
Compatibility:
➢Tolerant of water-miscible solvents
➢Cellulase enzyme stable
Electrolyte Sensitivity:
➢Electrolytes decrease solution viscosity (Especially Na,
Ca, AlCl3, AlSO4 )
pH Stability:
➢Slow to undergo acid hydrolysis.
➢Low pH lightens gum, high pH darkens, due to presence
of tannins.
➢Most stable at pH 5-9.
➢pH has significant influence on viscosity of solutions;
adjust after dissolving.
50
www.DuloMix.com
b. Tragacanth Gum
➢Exudate of Astragulas genus of shrubs.
Solution properties:
➢Bassorin Fraction-Swells in water, does not dissolve
➢Tragacanthin Fraction-Dissolves in water to give a
colloidal hydrosol.
➢Ethanol can be used to separate neutral and acidic
fractions.
pH and Temperature stability:
➢Gum used primarily for its resistance to heat and acidity.
➢Maximum stability at pH 5.
Synergisms:
➢Xanthan Gum or Propylene Glycol alginate in
combination with tragacanth gum yields pseudo plastic
emulsions.
51
www.DuloMix.com
Rheology:
➢Pseudo-plastic, Forms viscous mucilages, Thermally
reversible.
➢This mucilages are similar to pectin gels, which also
contains D-Glulactoronic acid.
➢Viscosity build proportional to methoxyl content of gum.
➢Bi-functional: viscosifies aqueous phase and emulsifies
dispersed oil phase.
Compatibility:
➢Tolerant of water-miscible solvents.
➢Viscosity decreases with increased ethanol and organic
solvent level.
Electrolyte Sensitivity:
➢Reacts with multivalent salts.
➢Trivalent metal ions gel or precipitate gum.
52
www.DuloMix.com
2. Seed Extracts
a.Guar Gum
➢Branched polysaccharide obtained from the seed of the
legume Cyamopis tetragonolobus.
Rheology:
➢Translucent solutions are pseudo plastic, viscous with
some elasticity.
➢Solutions can develop additional viscosity upon
heating especially if prepared in a cold process.
➢Possess no yield value.
➢Hydration time, a function of particle size.
pH Stability:
➢Stable over ph 3.5 to 10.5.
53
www.DuloMix.com
Gelation:
➢Form cross-linked, viscoelastic gels with borate and
metal ions.
➢Optimum pH for borate gel formation, 7.5 to 10.5.
➢Borate gels “melt” reversibly at pH less than 7
➢Solutions and borate gels are thermally reversible, Metal
ion gels are not reversible.
Compatibility:
➢Organic solvent insoluble, Tolerant of water-miscible
solvents
Electrolyte Sensitivity:
➢Forms cross-linked gels with multivalent cations and
borate.
54
www.DuloMix.com
c. Locust bean gum
➢Branched polysaccharide obtained from the seed of the carob
tree (ceratonia siliqua).
Rheology:
➢Pseudo plastic, viscous solution, thermally reversible,
possess no yield value, irreversibly degraded under high
shear.
Compatibility:
➢Organic solvent insoluble.
➢Tolerant of water miscible solvents.
Synergism:
➢Kappa carrageenan-Strong synergism-Adds elasticity,
makes gel brittle, more gummy, yields maximum gel
strength.
➢Xanthan gum- strong synergism-form elastic, non brittle
gels, although individually not gelling agent.
55
www.DuloMix.com
3. SEAWEED EXTRACTS
a. Alginates
➢Straight chain polysaccharide derived from brown seaweed.
➢Consists of a mixture of mannuronic acid and guluronic
acid units.
➢Alginates are mixture of Alginic acid and its sodium,
potassium, calcium and magnesium salts.
Rheology:
➢High guluronic acid yields brittle gels that have
syneresis.
➢High mannuronic acid yields elastic gels.
➢Addition of sequestrants gives Newtonian flow, Sodium
Alginate is pseudoplastic.
56
www.DuloMix.com
Compatibilities:
➢Organic solvent insoluble, compatible with Anionics and
Non-ionics, but viscosity loss at high concentrations.
➢Incompatible with Cationics and Amphoterics.
Electrolyte sensitivity:
➢Salt influences viscosity development.
➢Monovalent salt increases viscosity upon storage.
pH stability:
➢Sodium alginate is stable pH 5-10.
➢Propylene glycol is stable pH 3-8.
Synergism:
➢Xanthan gum imparts yield value, Increased pseudo
plasticity.
57
www.DuloMix.com
b. Carrageenan
➢Straight chain polysaccharide derived from seaweed.
➢A galactan with galactose residues linked in an altering α(1-
3) and β(1-4) arrangement.
Gelatin mechanism:
1. Disperse in cold water.
2. Dissolve by heating.
3. Add counter ion.
4. Cool to gelling temperature or below.
5. The gelling temperature is a function of the
concentration of gelling cations.
58
www.DuloMix.com
Types
Type Salt Water solubility Gel type Freeze/thaw
stability
Kappa Na Cool and hot stable Brittle, syneresis. None
Ca Soluble above 60°C Very brittle, syneresis. None
K Soluble above 60°C Strongest gel, brittle, None
syneresis.
Iota Na Cold and hot soluble Elastic, cohesive no Stable
syneresis.
Ca Thixotropic Strongest iota gel elastic, Stable
dispersion below cohesive, no syneresis.
60°C
K Soluble above 60°C Elastic, cohesive no Stable
syneresis.
Lambda All Cold and hot soluble Non gelling None
59
www.DuloMix.com
EMOLLIENTS
➢Emollients are topical treatments (treatments that are applied
directly to the skin). They reduce water loss from the outer layer
of skin (epidermis) by covering it with a protective film.
➢Emollients are also sometimes known as moisturizers.
Emollients come in several different forms, including:
➢soap substitutes
➢bath oils
➢moisturizing creams and ointments
How do emollients work?
➢The skin is made up of layers that perform several functions,
including storing water.
➢ Emollients keep the water in the skin where it is needed and
allow damaged skin cells on the skin’s surface to repair
themselves.
60
www.DuloMix.com
Types of Emollients
Two types
1. Leave-on emollients are an important part of a dry and
itchy skin care routine. They are classified according to how
much oil they contain:
a. Ointments are the greasiest. They’re often used for very
dry skin and at night-time.
b. Creams contain a mixture of oil and water. They’re less
greasy than ointments and can be easier to spread on the
skin.
c. Lotions are the least oily and feel the lightest but they
might need to be applied more often to keep the skin
hydrated.
61
www.DuloMix.com
2. Wash-off emollients or soap substitutes:
➢Washing and bathing products can sometimes contain
things like soap, colorings or fragrances which can irritate
your skin and make it worse.
➢Soap substitutes are unperfumed emollients which
cleanse the skin effectively but do not lather like soap,
therefore they can help prevent loss of moisture and drying
of the skin.
Soap substitutes
➢Certain skincare products can remove your skin’s surface
layer of natural oils.
➢These include: Liquid cleansers, shampoos, ordinary bubble
baths, shower gels.
62
www.DuloMix.com
➢This can make your skin dry and can further aggravate long-
term (chronic) skin conditions such as eczema.
➢Soap substitutes, such as aqueous cream or emulsifying
ointment, can be used instead of soap for hand washing and
bathing.
➢Aqueous cream can also be used as a substitute for shaving
foam.
63
www.DuloMix.com
REFERENCES
1. Harry’s cosmetology, 8th edition.
2. Martin’s ‘physical pharmacy’ 4th ed., varghese publishing
house, Bombay.
3. Poucher’s perfume cosmeics and soaps,10th edition.
4. Remington’s pharmaceutical sciences, 16th ed., mack
publishing house, pennysylvania, USA.
5. Sanju nanda, Arun Nanda, Khar.K Roop, Cosmetic
Technology, Birla Publications pvt.ltd, Delhi.
6. Pharmaceutical formulation and evaluation by B.M. Mithal.
7. https://www.dispersions-pigments.basf.com.
8. https://hse.ie/eng/health/az/E/Emollients/Types-of-
emollient.html
64
www.DuloMix.com
65
www.DuloMix.com