.
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.
Dr. Ciobanu Cristina
•• 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.
•
Dr. Ciobanu Cristina
•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).
Dr. Ciobanu Cristina
• Disadvantages:
• 1. Short shelf-life.
• 2. Unstable:- soluble phase separate slowly
• 3. Difficulty in handling
• 4. Proper Storage required.
Dr. Ciobanu Cristina
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).
Dr. Ciobanu Cristina
• 3. by composition:
Dr. Ciobanu Cristina
Dr. Ciobanu Cristina
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
Dr. Ciobanu Cristina
The role of emulsifier is: - to facilitate the dispersion of the internal phase into the external one; -to stabilize the emulsion.
Dr. Ciobanu Cristina
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.
Dr. Ciobanu Cristina
- 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
Dr. Ciobanu Cristina
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.
Dr. Ciobanu Cristina
Dr. Ciobanu Cristina
Dr. Ciobanu Cristina
Dr. Ciobanu Cristina
Sourse of image: https://www.linkedin.com/pulse/how-choose-fat-emulsifiers-animal-feeds-enhance-growth-kate-wu/
Dr. Ciobanu Cristina
Summary of HLB ranges and their applications
PREPARATION OF EMULSIONS
2 STAGES
Dr. Ciobanu Cristina
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.
Dr. Ciobanu Cristina
• 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
Dr. Ciobanu Cristina
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.
Dr. Ciobanu Cristina
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.
Dr. Ciobanu Cristina
Following an improper emulsification, or due to some external factors, the following changes may occur in emulsions:
Dr. Ciobanu Cristina
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).
Dr. Ciobanu Cristina
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).
Dr. Ciobanu Cristina
• 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.
Dr. Ciobanu Cristina
Dr. Ciobanu Cristina
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