emulsion

Group number: 02
Course: Physical Pharmacy
Course Code: 311

EMULSIONS
 The word "emulsion" comes from the Latin word for "to milk“.
EMULSION:
 An emulsion is a mixture of two or more
liquids that are normally immiscible
(nonmixable or unblendable).

INTRODUCTION
 Emulsions are part of a more general class of two-phase
systems of matter called colloids.
 Emulsion should be used when both the dispersed and the
continuous phase are liquids.
 Examples of emulsions include vinaigrettes, milk, mayonnaise,
and some cutting fluids for metal working. The photo-sensitive
side of photographic film is an example of a colloid.

TYPES OF EMULSIONS:
1- Oil in water emulsions
2- Water in oil emulsions
3- Multiple emulsions (O/W/O) or (W/O/W)
4- Microemulsions.

DIFFERENCE BETWEEN O/W AND W/O
EMULSIONS:
(o/w) (w/o)
 Water is the dispersion
medium and oil is the
dispersed phase.
 non greasy and easily
removable from the skin.
 used externally to provide
cooling effect e.g. vanishing
cream.
 preferred for internal use as
bitter taste of oils can be
masked.
 Oil is the dispersion medium
and water is the dispersed
phase.
 greasy and not water
washable.
 used externally to prevent
 evaporation of moisture
from the surface of skin e.g.
Cold cream.
 preferred for external use
likecreams.

 MULTIPLE EMULSIONS:
 Multiple emulsions are the emulsion system in which the
dispersed phase contain smaller droplets that have the same
composition as the external phase.
 The multiple emulsions are also considered to be of two types:
o Oil-in-Water-in-Oil (O/W/O) emulsion system
o Water-in-Oil-In-Water (W/O/W) emulsion system
TYPES OF EMULSIONS:

 Oil-in-Water-in-Oil:
In O/W/O systems an aqueous phase (hydrophilic) separates
internal and external oil phase. In other words, O/W/O is a system in
which water droplets may be surrounded in oil phase, which in true
encloses one or more oil droplets.
 Water-in-Oil-In-Water:
In W/O/W systems, an organic phase (hydrophobic) separates
internal and external aqueous phases. In other words, W/O/W is a
system in which oil droplets may be surrounded by an aqueous
phase, which in turn encloses one or several water droplets. These
systems are the most studied among the multiple emulsions.
TYPES OF EMULSIONS:

 MICROEMULSIONS:
 Clear, stable, liquid mixtures of oil, water and surfactant,
frequently in combination with a co-surfactant.
 In contrast to ordinary emulsion, Microemulsions form upon
simple mixing of the components and do not require the high
shear conditions generally used in the formation of ordinary
emulsions.
 The two basic types of Microemulsions are (o/w) and (w/o).
TYPES OF EMULSIONS:

 MICROEMULSIONS:
 Unlike the common macro emulsion in that:
1- Appear as clear transparent solution.
2- Diameter of internal phase droplets ranged between 10-
200nm.
3-Thermodynamically stable.
TYPES OF EMULSIONS:

 Name: AMMARAH MEHEK
 Roll number: 5
 Topic: DETECTION TESTS
EMULSIONS

DETECTION TESTS:
 Dilution test:
based on the solubility of external phase
of emulsion.
- o/w emulsion can be diluted with water.
- w/o emulsion can be diluted with oil.

 Conductivity Test:
 water is good conductor of electricity whereas oil is non-
conductor. Therefore, continuous phase of water runs
electricity more than continuous phase of oil.
DETECTION TESTS:

Dye-Solubility Test:
 when an emulsion is mixed with a water soluble dye such as
amaranth and observed under the microscope.
 if the continuous phase appears red, then it means that the
emulsion is o/w type as water is the external phase
 if the scattered globules appear red and continuous phase
colorless, then it is w/o type.
DETECTION TESTS:

DETECTION TESTS:
Fluorescence test:
 Oils give fluorescence.
 Under UV light, while water doesn’t. Therefore, O/W
emulsion shows spotty pattern while W/O emulsion
fluoresces.

EMULSIFYING AGENTS
• Emulsifying agents are substance that are soluble in both
water and fat and enable fat to be uniformly dispersed in water
as an emulsion.

CLASSIFICATION OF EMULSIFYING
AGENT:
TYPES TYPE OF FILM EXAMPLE
1. Synthetic(surface-
active agent)
emulsifying agent
monomolecular Anionic:-(pH : >8)
SOAP:
Potassium laurate
SULFATES:
Sodium lauryl sulfate
SULFONATES:
Dioctyl sodium sulfosuccinate
Cationic: (pH : 3-7)
Quaternary ammonium salt
Non-ionic:- (pH : 3-10)
Polyoxyethylene fatty alcohol
ethers
Sorbitan fatty acid esters

2. Natural
emulsifying agent
multimolecular
monomolecular
Hydrophilic collides:
Acacia
Gelatin
Lecithin
Cholesterol
3. Finely dispersed
solid
solid particles Collidal clays
Bentonite
Veegum
Metallic hydroxides
Magnessium
hydroxide

PRODUCT SOURCE AND
COMPOSITION
PRINCIPLE USE
Cetyl alcohol Chiefly C16H33OH Lipophilic thickening agent and
stabilizer for o/w lotion and
ointments
Methyl
cellulose
Series of methyl
ethers of cellulose
Hydrophilic thickening agent and
stabilizer for o/w emulsion; weak
o/w emulsifier

Stearic acid A mixture of solid acid
from fat , chiefly stearic
and palmitic
Lipophilic thickening
agent and stabilizer for
o/w lotion.
Sodium
carboxymethy
lcellulose
Sodium salt of
Carboxymethyl ester of
cellulose
Hydrophilic thickening
agent and stabilizer for
o/w emulsion
PRODUCT SOURCE AND
COMPOSITION
PRINCIPLE USE

Agar Cholic acid Ceatyl alcohol Albumin
Diacetyl
tartaric acid
ester
Casein Alginates Glycerol
Monostearate Egg yolk Gum Irish moss
(carrageenan)
Soap Mono sodium
phosphate
Ox bile extract Lecithin
LIST OF EMULSIFYING AGENTS:

LECITHIN: (Nonionic)
 One of the group of Phosphoglycerides found in various plants
and animals substances including egg yolk, nerve tissue,
semen and cell membrane.
 Naturally occurring phospholipid derived from soybean. Both
oil and water loving.
 Lecithin is a vitamin supplement and a dietary supplement.

 Most important component of cell. It can help nourish damage
cells and tissues and also help in keeping skin soft and supple
 Used in making surfactant, to improve flow property of
chocolate, to reduce cholesterol level and helps keep our
blood's cholesterol circulation freely.
 Lecithin is an emulsifier or mixing agent that help fat and
water stay together.

 Source:
Soybean and egg are good source of lecithin
 Example:
 Egg yolk, mayonnaise, ice cream, milk, cosmetics, lotion,
cheese, margarine ,coating

 SOAPS:
 Soaps or detergents may be anionic, cationic and nonionic.
 They are amphiphatic. One end sticks to oil (hydrophobic) and
one end sticks to water ( hydrophilic).
 Soap or synthetic detergent contain a long non polar tail and a
polar or ionic head. The non polar end of the molecule
dissolves well in non polar grease and oil while the polar or
ionic head dissolves in water. The tail of soap molecule
penetrate into oil or grease and break it up into tiny micelles.

 Cationic:
Quaternary ammonium salt of acetates, chlorides or bromides.
 Anionic:
Sodium alkyl sulfates and sodium alkyl benzene sulfonate.
 Non ionic:
These detergents are ester of alcohol having high molecular
mass.
Example: Polyoxyethylene fatty alcohol ethers

 DIACETYL TARTARIC ACID ESTER:
(Non ionic)
 DATEM is used to strengthen the dough by building a strong
gluten network. It is an emulsifier used in baking. It is used in
enlarging the physical volume of bread, improve the structure
of tissue , prolong shelf life and increase the soft feeling and
pliability
 It is used in crusty bread, chewy texture, biscuits, coffee
whitener, ice cream, salad dressing.

 DATEM appears to interact with the hydrophobic part of
gluten helping protein unfold and form cross linked structure.
It is used as emulsifier, dispersion agent to improve
emulsification and the inter-miscibility b/w oil and water.
 Dispersive in hot water, soluble in oil and fat or some kind of
organic dissolvent.
 It is use in butter to make taste better.

 GUM:
 Gum may be cationic, nonionic or anionic. eg: xanthan gum is
anionic(natural), cationic guar gum (semi natural) is cationic
and guar gum is nonionic ( natural) .
 Gum are hydrocollidal that binds, thicken and emulsify gluten
free ingredient.
 Guar gum is an emulsifier, thickener, stabilizer approved for
use in a wide range of food, cosmetics and pharmaceutical
 It thickens without application of heat

 It can act as a light emulsifier as it prevents oil droplets from
coalescing.
 Easily soluble in cold and hot water, resistance to oil, greases and
solvent, high viscosity, functional at low temperature, better
thickening agent
 In baking it increase dough yield, in dairy product it thicken milk,
yogurt and liquid cheese product, for meat it function as binder.
Used in dry soup, sweet desert, frozen food item.
 Guar gum as a water soluble fiber acts as bulk forming laxative, so it
claim to effective in promoting regular bowel movement and
relieving constipation
 Example:
Lotion, surfactant product , conditioner, ice cream, cosmetics,
baking food. etc

EMULSION INSTABILITY:
 The instability of pharmaceutical emulsions may be classified
as following:
 Flocculation and creaming
 Coalescence and breaking
 Phase inversion
 Miscellaneous physical and chemical change

 FLOCCULATION:
The small spheres of oil join
together to form clumps or flocks
which rise or settle in the emulsion
more rapidly than individual
particles.
EMULSION STABILITY:

 It is the concentration of the floccules of the internal phase
form upward or downward layer according to the density of
internal phase.
 CREAMING:
EMULSION STABILITY:

 CREAMING:
Stokes equation included the factors that
affect the creaming process:
 dx/dt=d2 (pi-pe)g/18n
 dx/dt=rate of setting
 D=diameter particle
 p=density of internal phase and external phase
 g=gravitational constant
 n=viscosity of medium
EMULSION STABILITY:

 Factors affect creaming:
 Globule size:
↑globule size ↑creaming
 The density of the internal phase and External phases:
pi-pe=0 dx/dt=0
pi-pe=-ve[i.e.-ve velocity upward creaming]
pi-pe=+ve [downward creaming]
 Gravity:
Constant, however centrifugation is applied
 Velocity:
↑ ↓creaming
EMULSION STABILITY:

 COALESCENCE:
 It is the process by which emulsified particles merge
with each to form large particles.
EMULSION STABILITY:

 BREAKING:
 Due to coalescence and creaming combined,the oil
separates completely from water so that it floats at the
top in a single, continuous layer.
EMULSION STABILITY:

 DIFFERENCE BETWEEN CREAMING AND
CRACKING:
CREAMING BREAKING
 Formation of upward and
downward layer.
 Separation of emulsion to
upward oily layer and
downward aqueous layer.
 Reversible.  Irreversible.
 Partial or no coalescence.  Complete fusion.
EMULSION STABILITY:

 COALESCENCE AND BREAKING:
PHASE INVERSION:
 In phase inversion o/w type emulsions changes into w/o type
and vice versa.
 It is a physical instability.
It may be brought about by:
 the addition of an electrolyte e.g. addition of calcium chloride
into o/w emulsion formed by sodium stearate can be inverted to
w/o.
 by changing the phase volume ratio.
 by temperature changes.
EMULSION STABILITY:

 Phase inversion can be minimized by:
o using the proper emulsified agent in adequate
concentration.
o keeping the concentration of dispersed phase between
30 to 60%.
o storing the emulsion in a cool place.
EMULSION STABILITY:

 CRACKING:
o When an emulsion cracks during preparation. i.e the primary
emulsion does not become white but acquires an oily
translucent appearance.
o In such a case it is impossible to dilute the emulsion nucleus
with water and the oil separates out.
EMULSION STABILITY:

 Cracking of emulsion can be due to:
1-addition of an incompatible emulsifying agent:
e.g. monovalentsoap + divalent soap
2-chemical or microbial decomposition of emulsifying agent:
e.g. alkali soap decompose by acid.
3-exposure to increased or reduced temperature
4-addition of common solvent.
EMULSION STABILITY:

 When two immiscible liquids are agitated together so that one
of the liquids is dispersed as small droplets in the other. To
prevent coalescence between globules, it is necessary to use
emulsifying agent.
 Emulsifying agent may be classified in accordance with the
type of film they form at the interface between the two
phases.
 There are three types of films:
 Monomolecular Films.
 Multimolecular Films.
 Solid Particle Films.
MECHANISM OF ACTION

1. Monomolecular Film:
 Coherent monomolecular film.
 Flexible film formed by SAA.
 Can prepare O/W or W/O emulsion.
 Lower surface tension and increase stability of emulsions.
Examples:
 Potassium Laurate
 Polyoxyethylene sorbitan monooleate
MECHANISM OF ACTION

2. Multi-molecular Film:
o Strong rigid film formed. mostly by the hydrocolloid.
o Produce o/w emulsion.
o Have low effect on surface tension.
Examples:
o Acacia
o Gelatin
MECHANISM OF ACTION

3. Solid Particle Film:
o Film formed by solid particles that are small in size compared
to the droplet of the dispersed phase.
o Can form o/w and w/o emulsions.
o Particles must be wetted by both phases in order to remain
at the interface and form stable film.
Examples:
o Bentonite
o Graphite
o Magnesium Hydroxide
MECHANISM OF ACTION

THE HLB SYSTEM:
H • HYDROPHILE
L • LIPOPHILE
B • BALANCE

 DEFINATION:
o The ratio between the hydrophilic portion of the molecule to
the lipophilic portion of the molecule.
 RELATION:
higher the
HLB
higher the
hydrophilicity
THE HLB SYSTEM:

 HLB NUMBER VS SOLUTION
FUNCTION
HLB Range Application
4-6 Water/Oil emulsifiers
7-9 Wetting agents
8-18 Oil/water emulsifiers
13-15 Detergents
10-18 Solubilizers

 USES OF HBL:
predict
haow
surfactant
behave
study the
chemistry
of
surfactant

 CALCULATION OF HLB:
• Griffin Equation:
HLB = 20 (1-S/A)
Where
• Saponification of
num of esterS
• acid num of fatty
acidA

 Davis equation:
HLB = H.G.N – L.G.N +7
Where
• HYDROPHILIC GROUP
NUMBER
H.G.N
• LIPOPHILIC GROUP
NUM
L.G.N
 CALCULATION OF HLB:

METHODS OF PREPARATION:
 Continental or Dry Gum Method:
o Emulsifier is triturated with the oil in perfectly dry porcelain
mortar
o water is added at once
o triturate immediately, rapidly and continuously (until get a
clicking sound and thick white cream is formed, this is
primary emulsion)
o the remaining quantity of water is slowly added to form the
final emulsion

 English or Wet Gum Method:
o Triturate gum with water in a mortar to form a mucilage
oil is added slowly in portions the mixture is triturated
o After adding all of the oil, thoroughly mixed for several
minute to form the primary emulsion
o Once the primary emulsion has been formed remaining
quantity of water is added to make the final emulsion.

 Bottle or Forbes Bottle
Method:
o It is extemporaneous preparation for volatile oils or oil with
low viscosity.
o gum + oil (dry bottle)
o Shake
o water (volume equal to oil) is added in portions with
vigorous
o Shaking to form primary emulsion
o Remaining quantity of water is added to make the final
emulsion.

 Auxiliary Method:
o An emulsion prepared by the Wet Gum or the Dry Gum
method can generally be increased in quality by passing it
through a HAND HOMOGENIZER.
o In this apparatus the pumping action of the handle force
the emulsion through a very small orifice.
o That reducing the dispersed droplet size to about 5 microns
or less.

 Nascent Method or In Situ Soup
Method:
o The two types of soaps developed by this method are calcium
soaps and soft soaps.
o Calcium soaps are W/O emulsion that contain certain
vegetable oil, such as oleic acid, in combination with Lime
water [ calcium hydroxide solution ca[0H]2 ].
o They are prepared simply mixing equal volumes of the oil and
lime water.

 Beaker Method:
o The most appropriate method for preparing emulsion from
surfactants or other non gum emulsifiers is to begin by
dividing components into water soluble and oil soluble
components.
o All oil soluble components are dissolved in the oil phase and
water soluble components dissolved in the water in a
separate beaker.
o Oleaginous components are melted and both phase are
heated to approximately,70 cover a water bath.
o The internal phase is then added to the external phase with
stirring until the room temperature.
o The mixing of such emulsions can be carried out in a beaker.

 CHEMICAL INDUSTRY:
 Cationic:
o Antimicrobial properties.
 Nonionic:
o Low toxicity.
o Ability to be injected directly into the body.
o Compatibility with many drug ingredients.
USES OF EMULSIONS

AGRICULTURE INDUSTRY:
 Used as delivery vehicles for insecticides, fungicides
and pesticides.
 Allows chemicals to be effectively diluted and provides
improved spray ability.
USES OF EMULSIONS

USES OF EMULSIONS
 COSMETIC:
 Allow dilution of active ingredients to an optimal
concentration.
 Delivery vehicle for many hair and skin conditioning agents.
Example: hair conditioners
 SURFACTANT TECHNOLOGY:
 Reduced odor and flammability
 Benefits over solvent containing systems because of.
Example: paints and inks

 FOOD:
 Many food products are in the form of emulsions.
Example: milk (naturally occurring emulsion) , Salad dressings,
gravies and other sauces, whipped dessert toppings, peanut
butter, and ice cream
 FIRE EXTINGUISHING:
 Effective at extinguishing fires on small, thin-layer spills
of flammable liquids
USES OF EMULSIONS

Pharmaceutical Application:
 It covers the unpleasent taste
 Increase absorptin rate.
 Topical emuslions are washable.
 Having acceptable viscosity.
 Less greasy.
 Controlled drug release.
 Increased Bioavailability.
 Protection of thermolibile drugs.
 Reduce Patients Variability.
01/04/2015 GROUP NO : 05

› Depending on the use, emulsions should be packed in suitable
containers.
› for oral use : usually packed in well filled bottles having an air tight
closure.
› Light sensitive products : packed in amber colored bottles.
› For viscous emulsions : wide mouth bottles should be used.
› The label on the emulsion should mention that these products have
to be shaken thoroughly before use.
› External use products should clearly mention on their label that
they are meant for external use only.
› Emulsions should be stored in a cool place but refrigeration should
be avoided as this low temperature can adversely effect the
stability of preparation.

emulsion

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