The document outlines the fundamentals of emulsions in pharmaceutical dispensing, including definitions, properties, types, advantages, and disadvantages. It discusses preparation methods, emulsifying agents, stability issues, and various applications for both oral and external use. Key points emphasize the importance of proper formulation to ensure stability and effectiveness in drug delivery.

1. EXTEMPORANEOUS DISPENSING
OF:
EMULSIONS
1
COURSE TITLE: DISPENSING PHARMACY
COURSE CODE: 510-T
COURSE INCHARGE: SHUMAILA QADIR

2.  Define Emulsions
 Discuss properties, importance and types of emulsions
 Determine the preparation of emulsions
 Discuss the problems associated with emulsions
 List the commonly used emulsifying agents
 Give the examples of official oral emulsions
2

3. EMULSIONS
 An emulsion is a disperse system consisting of two immiscible
liquids, one of which (the disperse phase) is finely divided and
distributed through the other (the continuous phase).
 The dispersed phase is referred to as the
Internal phase
 The dispersion medium as the External or
Continuous phase
3

4.  Generally, to prepare a stable emulsion, an emulsifying agent is necessary
 Because the external phase of an emulsion is continuous, an O/W emulsion may be diluted
with water or an aqueous preparation, and W/O emulsion with an oleaginous or oil miscible
liquid
4

5. Emulsions
B C D
A.: Two immiscible liquids not emulsified
B. An emulsion of phase A dispersed in Phase B
C. Unstable emulsion slowly separates.
D.The emulsifying agent places it self on the interface between phase A and phase B and
stabilizes the emulsion.
Phase A
Phase B
A
5

6. Advantages
6
 To deliver drugs that exhibit a low aqueous solubility.
 Pharmaceutical emulsions may be used to mask the taste of therapeutic agents, in which the drug is
dissolved in the internal phase of an o/w emulsion.
 Emulsions may be commonly used to administer oils that may have a therapeutic effect. e.g.
liquid paraffin
 Pharmaceutical emulsions may be employed to administer drugs to patients who have difficulty
swallowing solid-dosage forms.

7. Disadvantages
7
 Pharmaceutical emulsions are thermodynamically unstable and therefore must be
formulated to stabilize the emulsion from separation of the two phases.
 Pharmaceutical emulsions may be difficult to manufacture.

8. Types of emulsions
Simple emulsions (Macroemulsions)
 Oil-in-water (O/W)
 Water-in-oil (W/O)
Multiple emulsions
 Oil-in-water-in-oil (O/W/O)
 Water-in-oil-in-water (W/O/W)
8

9. Types of emulsions
9
w/
o/w
Multiple
emulsions
o/
w/o

10. EMULSIFYING
AGENTS
10
Natural
Emulsifying
Agents
• Acacia is most
frequently use.
Tragacanth and Agar
- thickening agents in
Acacia - emulsified
products.
Carbohydrates:
 acacia,
 tragacanth
 agar
 pectin
Proteins
 gelatin,
 egg yolk,
 casein
Finely
Divided
Solids
•These materials
generally form O/W
emulsions
Colloidal clays including
Bentonite,
Magnesium hydroxide
Aluminum hydroxide

11. EMULSIFYING
AGENTS
11
Synthetic (wetting agents), which may be
Anionic, Cationic, Nonionic
Anionic:
• Triethanolamine oleate
• Sodium lauryl sulfate
Cationic:
• Benzalkonium chloride
Nonionic:
• Sorbitan esters (span)
• Polyethylene glycol 400
monostearate
• Polyoxyethylene
sorbitan esters
(Tweens)

12. OTHER ADDITIVES
12
 Antioxidants
 Preservatives
 Coloring agent
 Flavoring agent

13. Qualities Required for
Emulsifiers
13

Must be compatible with other ingredients in the formula

Must not interfere with the stability and efficacy of the therapeutic
agent

Must be stable to microorganisms

Must be non-toxic

Must possess little or no odor, taste or color

Must promote emulsification and maintain stability of the emulsion
for intended shelf-life

14. PREPARATION OF
EMULSIONS
14
 On small scale

mortar and pestle can be used
 For large scale production

mechanical stirrers , homegenizers,
colloidal mill are used

15. Methods of Preparation
15
1. Continental or Dry gum method
2. English or wet gum method
3. Bottle or Forbes bottle method

16. Continental or Dry gum method
(G + O + W )
16
 The method is also referred to as the “4:2:1” method because for every 4 parts (volumes) of oil, 2
parts of water and 1 part of gum are added in preparing the initial or primary emulsion.
 For instance, if 40 mL of oil are to be emulsified, 20 mL of water and 10 g of gum would be
employed, with additional water or other formulation ingredients being added afterward to
the primary emulsion

17. Continental or Dry Gum Method
17
the remaining quantity of water is slowly added to form the final emulsion
triturate immediately, rapidly and continuously (until get a clicking sound and thick white
cream is formed, this is primary emulsion)
Other liquid formulative ingredients that are soluble in or miscible with the external phase
may then be added to the primary emulsion with mixing.
two parts of water then added at once
Emulsifier is triturated with the oil in perfectly dry porcelain mortar

18. English or Wet Gum method ( G + W + O )
Once the primary emulsion has been formed remaining quantity of water is added to
make the final emulsion
after adding all of the oil, thoroughly mixed for several minute to form the primary
emulsion
the mixture is triturated
oil is added slowly in portions
triturate gum with water in a mortar to form a mucilage
21

19. Bottle or Forbes Bottle Method
(G+O+W)
19
 For the extemporaneous preparation of emulsions from volatile oils or oleaginous
substances of low viscosities, the bottle method is used.

20. remaining quantity of water is added to make the final emulsion
water (volume equal to oil) is added in portions with vigorous shaking to
form primary emulsion
Shake
gum + oil (dry bottle)
gum + oil (dry bottle)
20

21. PROBLEMS
21
Flocculation - is the joining together of globules to form large clumps or floccules which rise
or settle in the emulsion more rapidly than do the individual particles
Creaming is the rising (upward creaming) or settling (downward creaming) of globules or
floccules to form a concentrated layer at the surface or to the bottom of the
emulsion
Coalescence
and
breaking
unlike creaming, the coalescence of globules and the subsequent breaking of an
emulsion are irreversible processes. In creaming, the globules are still
surrounded by a protective coating or sheath of emulsifying agent and may
redispersed simply by agitating the product.
Deterioration by
Microorganis
m
Molds, yeast and bacteria may bring about decomposition and contamination of
the emulsion. Preservatives should be more fungistatics than bacteriostatic
Miscellaneous
Physical and
Chemical Change
Light and rancidity affect the color and the odor of oils and may destroy their
vitamin content. Freezing and thawing and high temperature result in the
coarseness and breaking of an emulsion.

22. 22

23. Emulsion Stability
23
A stable emulsion is characterized by the following:
1. Absence of flocculation and creaming
2. Absence of coalescence of globules and separation of the layers
3. Absence of deterioration due to microorganisms
4. Maintenance of elegance with respect to appearance, odor, color and consistency

24. Test for identification of emulsion type:
 Dilution test (miscibility test)
 Staining test (dye solubility test)
 Conductivity measurement
24

25. 25
1. Dilution test (miscibility test)

26. This test is based on the basic principle that water is a good conductor of electricity. Therefore in case of o/w
emulsion , this test will be positive as water is the external phase. In this test. An assembly consisting of a pair
of electrodes connected to a lamp is dipped into an emulsion. If the emulsion is o/w type, the lamp glows.
26
2.Conductivity measurement

27. In this 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 and the dye will dissolve in it to give color but if the scattered globules
appear red and continuous phase colorless, then it is w/o type.
27
3. Staining test (dye solubility test)

28. SHELF LIFE OF ORAL
EMULSIONS
28
 Unpreserved emulsions deteriorate rapidly but stabilized and preserved systems may be
stored

29. CONTAINERS FOR ORAL
EMULSIONS
29
 Emulsions should be supplied in well-filled
containers with air tight closures
 For viscous preparations, wide- mouthed
amber glass bottles are more appropriate

30. SPECIAL LABELS AND ADVICE FOR
PATIENTS
SHAKE THE BOTTLE
STORE IN A COOL PLACE BUT
AVOID FREEZING
30

31. Examples
31
Oral use
 Cod-liver oil emulsions
 Liquid paraffin oral emulsion
 Castor oil emulsions

32. EMULSIONS FOR EXTERNAL USE
Applications Liniments
Lotions Creams
35

33. Applications, Liniments &
Lotions
33
 These are liquid or semi-solid emulsions designed for application to
the skin.

34. Shelf-life of Applications,
Liniments & Lotions
34
 These are generally stable preparations

35. Containers for Applications,
Liniments & Lotions
35
 Amber fluted bottles or jars are used for extemporaneously prepared products.
 Some manufactured products may be packed in plastic containers.

36. SPECIAL LABEL AND ADVICE FOR
PATIENTS
36
SHAKE THE BOTTLE

37. REFERENCE
37
 Pharmaceutical practice by D.M. Collette

Ch # 13