EMULSIONSGroup number: 02

Course: Physical PharmacyCourse Code: 311

EMULSIONSThe 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).

INTRODUCTIONEmulsions 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 emulsions2- Water in oil emulsions3- Multiple emulsions (O/W/O) or (W/O/W)4- Microemulsions.

DIFFERENCE BETWEEN O/W AND W/OEMULSIONS:

(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.

( O/W )

( W/O )

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 systemo 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 phaseof 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 phaseif 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 EXAMPLE1. Synthetic(surface-active agent) emulsifying agent

monomolecular Anionic:-(pH : >8) SOAP:Potassium laurate SULFATES:Sodium lauryl sulfate SULFONATES:Dioctyl sodium sulfosuccinateCationic: (pH : 3-7)Quaternary ammonium saltNon-ionic:- (pH : 3-10)Polyoxyethylene fatty alcohol ethersSorbitan fatty acid esters

2. Natural emulsifying agent

multimolecular monomolecular

Hydrophilic collides:AcaciaGelatinLecithinCholesterol

3. Finely dispersed solid

solid particles Collidal claysBentonite VeegumMetallic 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 carboxymethylcellulose

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 lecithinExample: 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

EMULSION STABILITY:

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 appliedVelocity:

↑ ↓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 Acaciao 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 Bentoniteo Graphiteo 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

hydrophilici

ty 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 NUMBERH.G.

N• LIPOPHILIC GROUP

NUML.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 onceo 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.

METHODS OF PREPARATION:

Bottle or Forbes Bottle Method:

o It is extemporaneous preparation for volatile oils or oil with low viscosity.

o gum + oil (dry bottle)o Shakeo water (volume equal to oil) is added in portions with

vigorouso Shaking to form primary emulsiono Remaining quantity of water is added to make the final

emulsion.

METHODS OF PREPARATION:

METHODS OF PREPARATION:

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.

METHODS OF PREPARATION:

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.

METHODS OF PREPARATION:

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 tasteIncrease 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

STORAGE & PACKAGING :

› 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.