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LECTURER – DR. CRISTINA CIOBANU,

UNIVERSITY ASSISTANT

DRUG TECHNOLOGY DEPARTMENT

EXTEMPORANEOUS PHARMACEUTICAL TECHNOLOGY

State University of Medicine and Pharmacy “Nicolae Testemitanu”

Emulsions

•Emulsions are more or less viscous liquid

pharmaceutical products consisting of a

dispersed system of two immiscible liquid

phases and made with emulsifiers, for

internal or external administration.

•

Dr. Ciobanu Cristina

•They are micro-heterogeneous dispersion

systems in which the diameter of dispersed

liquid droplets is generally between 0.5

and 50 μm, thus the particles being visible

under the usual microscope.


http://www.dictionary.com/browse/heterogeneous

•• The term emulsion derives from the Latin

word "molgo, ere" – to milk and has

been used in the pharmaceutical field

since the 17th century, thus designating all

the medicinal liquids with a milk-like

appearance.

•


•The scientific foundation of the emulsification theory and explanation of the underlying phenomena of emulsion formation began only in the second part of the last century. Dr. Ciobanu Cristina

In pharmaceutical practice, emulsions have the following

advantages:

1. Emulsions ensure the simultaneous and accurate administration

of two immiscible liquids;

2. Emulsification can mask the unpleasant taste of some

medicines and may facilitate the administration of some

viscous medicinal substances;

3. Emulsification helps absorption of drugs, ensuring a faster and

better absorption.

4. Sustained Release Medication.

5. Nutritional supplement.

6. Diagnostic purpose (x-rays examination).

7. External use preparation (Cream, Lotion, Foam, Aerosol).


• Disadvantages:

• 1. Short shelf-life.

• 2. Unstable:- soluble phase separate slowly

• 3. Difficulty in handling

• 4. Proper Storage required.


CLASSIFICATION: 1. by the number of components:

- proper emulsions (3 main parts);

- pseudo- or quasi-emulsions (2 main parts - no emulsifier).

In quasi-emulsions, the merging of dispersed droplets is hampered

by the high viscosity of the continuous phase

2. by origin:

- natural (milk, latex of various plants);

- artificial (pharmaceutical emulsions).


• 3. by composition:


IDENTIFICATION TESTS FOR EMULSION

Dilution test

Conductivity test

Dye test (change the color)

Paraffin wax plate test

Fluorescence test

Cobalt chloride paper test Dr. Ciobanu Cristina

EMULSIFIERS –THEIR ROLE AND MODE OF ACTION


The role of emulsifier is: - to facilitate the dispersion of the internal phase into the external one; -to stabilize the emulsion.


If an emulsifier is added (e.g. a small amount of soap), the emulsification is much easier, while the

separation is much slower.

Emulsifiers increase to some extent the viscosity of the environment, thus particle mobility becomes lower, droplet approaching and merging is hampered.


- reduce interfacial tension (facilitate dispersion);

- form a layer around the particles (inhibit the tendency of small particles to merge);

- give an electrical charge to dispersed particles

- increase the viscosity of the environment.

1. Natural:

a. Vegetable source: Gum acacia, Tragacanth, Agar,

Starch, Pectin, Iris Moss.

b. Animal source: Wool Fat, Egg Yolk, Gelatin.

2. Semi synthetic: Methyl cellulose, Na CMC


3. Synthetic:

a. Anionic: Sodium Lauryl Sulphate

b. Cationic: Cetrimide, Benzalkonium chloride.

c. Non-ionic: Glyceryl ester- glyceryl monoesters etc.

4. Inorganic: Milk of magnesia, Mg oxide, Mg trioxide etc.

5. Alcohols (polyoles): Carbowax, Cholesterol and Lecithin.



Sourse of image: https://www.linkedin.com/pulse/how-choose-fat-emulsifiers-animal-feeds-enhance-growth-kate-wu/


Summary of HLB ranges and their applications

PREPARATION OF EMULSIONS

2 STAGES


1. PREPARING A PRIMARY EMULSION

2. PREPARING THE FINAL EMULSION - Make up the volume of emultion by dilution with vehicle.

INCLUSION OF DRUG SUBSTANCES IN EMULSIONS.

• Hydrosoluble substances dissolve in 1 / 3-1 / 4 of the quantity

• of water intended for dilution of the primary emulsion, and the

obtained solution is added to the finished emulsion.

• Liposoluble substances (camphor, menthol, anesthetics, vitamins,

pollutants, hormones, etc.) with the exception of salicylate phenyl and

benzonaphthol, are previously dissolved in oil, increasing the amount

of emulsifier proportional to a of the dissolved substances, then

emulsify as described above.


• Water and oil -insoluble substances (sulfamides) should be transformed first

very fine powder, then triturated with the emulsion

• Phenyl salicylate and benzonaphtol should be included as a very fine powder

trituration with the emulsion obtained.

• Liquids (tinctures, fluid extracts, alcoholic solutions, syrups

etc.) is added to the resulting emulsion directly into the delivery bottle


EMULSION UTENSILS AND APPLIANCES

• Appliances used at the pharmacy level

• • Generally mortars of suitable size are used to prepare emulsions in the pharmacy. They should be 2 to 3 times bigger than the emulsion

volume.

• Successful emulsification also depends on the shape of the mortar and

pestle. Mortars with higher and sharper walls are preferred. The

pestle ensures a maximum contact surface with the mortar walls.


EMULSION STABILIZATION

• The most important requirement that emulsions have to meet is to be

stable.

• Stability, practically, means the unchanged maintenance of the

degree of dispersion and homogeneous dispersion of the internal

phase particles in the external phase, respectively maintaining the

initial appearance of the preparation.


Following an improper emulsification, or due to some external factors, the following changes may occur in emulsions:


Schematic representation of the various breakdown processes in emulsions.

EMULSION CONTROL

Control methods provided by F.R. X:

- appearance: emulsions have a milk-like and homogeneous appearance. Color, smell and taste are characteristic of the components. Diluted with the external phase at a ratio of 1:10, emulsions must remain homogeneous (4.5x magnifying glass examination);

- total container mass,

-dosage.

Other emulsion control methods: -determination of emulsion type by coloring method, dilution method and electric conductivity method; - determination of de-emulsifying type; - determination of particle size; - determination of emulsion stability (by centrifugation).


EMULSION OF BENZYL BENZOATE –

• Rp.: Emulsi Benzylii benzoatis 100,0

• D. S. Externally, in scabies

•

• Prescribed liquid drug form is an emulsion for external

use, containing benzyl benzoate - oily liquid, practically

insoluble in water. This emulsion is used for the

treatment of scabies and pediculosis ( hair or body lice).


• Emulsion of benzyl benzoate for adults is of 20 %, for

children till 12 years of 10 %.

• To prepare 100.0 g of the emulsion, 20.0 g of benzyl

benzoate is taken and, 2.0 g of medicinal soap or T-2

emulsifier and 78.0 g of warm water. Soap (or T-2 emulsifier)

dissolves in warm water, add benzyl benzoate is vigorously

stirred (if necessary, filter).. The finished preparation is

released with the mention 'Shake before administration'.

Validity -7 days.



W.V.D

Nr. of prescription Date.

Aquae purificatae calidae 78 ml

Sapo medicinalis 2,0

Benzyli benzoatis 20,0

Total mass 100.0 Prepared

Verified

Deliverd

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