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PMQA > [MIDTERMS] PMQA LEC - Emulsions > Flashcards

[MIDTERMS] PMQA LEC - Emulsions Flashcards

1
Q

A thermodynamically unstable two-phase system consisting of at least two immiscible liquids, one of which is dispersed in the form of small droplets throughout the other, and an emulsifying agent.

A

Emulsions

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2
Q

Four (4) Types of Emulsions

A
  1. Oil-In-Water Emulsions
  2. Water-In-Oil Emulsions
  3. Multiple Emulsions
  4. Microemulsion
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3
Q

Such as oils, petroleum hydrocarbons, and/or waxes are the dispersed phase, and water or an aqueous solution is the continuous phase. Oil is dispersed as droplets in an aqueous medium. Formed if the aqueous phase constitutes 45% of the total weight and hydrophilic emulsifier is used. These are used topically, orally, or parenterally.

A

Oil-In-Water Emulsions

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4
Q

Water is dispersed as droplets in an oil or oleaginous medium. Used for external preparations when emollient, lubricating, or protective properties are desired.

A

Water-In-Oil Emulsions

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5
Q

Appear as translucent or transparent and have droplet diameter in the nanometer range (100A-1000A). These are thermodynamically stable, optically transparent isotropic mixtures of a biphasic o/w system stabilized with surfactants. Use for more rapid and efficient delivery of drugs following oral or transdermal drug delivery system.

A

Microemulsion

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6
Q

It is also known as Brookefield.

A

Viscosimeter

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7
Q

It determines the viscosity of disperse system.

A

Viscosimeter

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8
Q

It refers to the rapid formation of aggregates or emulsion droplets, due to no protective barrier is present at the interface of the water and oil droplets and has very low insufficient emulsifier coverage.

A

Coalescence

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9
Q

It is the result of the interaction of relativity weak particles, which may have sufficient emulsifier coverage and therefore prevent coalescence. It is differentiated from coalescence, by the fact that the interfacial film remains intact, and therefore aggregation maybe reversed.

A

Flocculation

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10
Q

It refers to the separation of the concentrated emulsified droplets (the internal phase) from the continuous phase. It usually “floats” on top of the continuous phase in the container.

A

Creaming

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11
Q

It is the reverse of Creaming, wherein the less concentrated emulsified droplets (the external phase) separates from the discontinuous phase in the container.

A

Sedimentation

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12
Q

They help the production of stable dispersion by reducing interfacial tension and then maintaining the separation of the droplets by forming barrier at the interface.

A

Emulsifying Agents

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13
Q

(T/F): If the emulsifying agent is more soluble in water (hydrophilic), then water will be the continuous phase and an oil-in-water emulsion will be formed.

A

T

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14
Q

(T/F): If the emulsifying agent is more soluble in oil (lipophilic), then water will be the continuous phase and an water-in-oil emulsion will be formed.

A

T

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15
Q

Three (3) Naturally Occurring Emulsifying Agents

A
  1. Polysaccharides
  2. Semi-Synthetic Polysaccharides
  3. Sterol-Containing Substances
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16
Q

The best emulsifying agent for extemporaneously prepared oral emulsions as it forms thick film at the oil-in-water interface to act as the barrier to coalescence. It is too sticky for external use.

A

Acacia

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17
Q

Increase the viscosity of an emulsion and prevent creaming. Does not contain oxidase and advantage of few amount needed in formulation. Coarser than acacia emulsion. Anionic and difficult to hydrate, used mainly for its effect in viscosity.

A

Tragacanth

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18
Q

Emulsifier that is used in the same proportion as tragacanth.

A

Pectin

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19
Q

Provides good emulsion stabilization in concentration of 0.5% to 1%. May be anionic or cationic, depending on its isoelectric point.

A

Gelatin

20
Q

Prepared from an acid-treated precursor, used in acidic media.

A

Type A Gelatin (+)

21
Q

Prepared from an alkali-treated precursor, used in basic media.

A

Type B Gelatin (-)

22
Q

Low viscosity grades of methylcellulose and CMC will form o/w emulsion.

A

Semi-Synthetic Polysaccharides

23
Q

It is nonionic and induces viscosity. Used as the primary emulsifier with mineral oil and cod liver oil, and yields an o/w emulsion. Usually in 2% concentration.

A

Methylcellulose

24
Q

It is anionic and is usually used to increase viscosity. It tolerates alcohol up to 40%. Forms basic solution. Precipitates in the presence of free acids.

A

Carboxymethylcellulose (CMC)

25
Q

These act as water-in-oil emulsifying agents.

A

Sterol-Containing Susbtances

26
Q

Three (3) Classifications of Surfactants

A
  1. Anionic Surfactants
  2. Cationic Surfactants
  3. Non-Ionic Surfactants
27
Q

These are organic salts, which, in water have the surface active anion. They are compatible with some inorganic cations and with large organic cations. Widely used in external preparations such as o/w emulsifying agents. Must be in ionized form to be effective. Generally stable at alkaline pH.

A

Anionic Surfactants

28
Q

These are usually quarternary ammonium compounds which have the surface active cation and so are sensitive to anionic surfactants such as soaps. Used in the preparation of o/w emulsion for external use. Must be in their ionized form to be effective. Emulsion formed are generally stable at acidic pH. Have antimicrobial activity.

A

Cationic Surfactants

29
Q

Synthetic materials and largest group of surfactants. Used to produce oil-in-water or water-in-oil emulsions for both external and internal use. These are compatible with both anionic and cationic substances. Highly resistant to pH change. Emulsion formed depends on HLB number.

A

Non-Ionic Surfactants

30
Q

Substances adsorbed in the water interface to form coherent film. If particles are preferentially wetted by oil or by water, water-in-oil and an oil-in-water emulsion formed, respectively.

A

Finely Divided Solids

31
Q

It is usually between 1 and 20 is allocated to an emulsifying agent and represents the relative proportions of lipophilic and hydrophilic molecule, and produce an o/w emulsion.

A

HLB Number

32
Q

(T/F): HLB 3-6 indicate hydrophilic molecule, produce water-in-oil emulsion.

A

F / Hydrophilic / LIPOPHILIC

33
Q

(T/F): HLB 8-18 indicate lipophilic molecule, produce oil-in-water emulsion.

A

F / Lipophilic / HYDROPHILIC

34
Q

Five (5) Methods of Preparation

A
  1. Continental or Dry Gum Method
  2. English or Wet Gum Method
  3. Bottle or Forbes Bottle Method
  4. Auxiliary Method
  5. In-Situ Soap Method
35
Q

The method is also referred to as the “4:2:1” method because for every 4 parts of oil, 2 parts of water and 1 part of gum are added in preparing the initial or primary emulsion. Addition of gum to oil (mixing lightly to disperse), followed by adding all water and stir continuously & vigorously. Continuous trituration for further 2-3 minutes to produce white stable emulsion. The whiter the product, the smaller the globules. Other ingredients should be added gradually up to its final volume.

A

Continental or Dry Gum Method

36
Q

By this method, the same proportions of oil, water, and gum are used as in continental or dry gum method, but the order of mixing is different. Generally mucilage of the gum is prepared by triturating granular acacia with twice its weight of water in mortar.

A

English or Wet Gum Method

37
Q

For the extemporaneous preparation of emulsions from volatile oils or oleaginous substances of low viscosities, the bottle method is useful. In this method, powdered acacia is placed in dry bottle, two parts of oil are then added, and the mixture is thoroughly shaken in the capped container.

A

Bottle or Forbes Bottle Method

38
Q

An emulsion prepared by either the wet gum or the dry gum methods can generally be increased in quality by passing it through hand homogenizer. The hand homogenizer is less efficient in reducing the particle size of very thick emulsions, and it should not be employed for emulsions containing high proportion of solid matter because of possible damage to the valve.

A

Auxiliary Method

39
Q

The two types of soaps developed by this method are calcium soaps and soft soaps. Calcium soaps are water-in-oil emulsions, which contain certain vegetable oils, such as oleic acid, in combination with limewater, and are prepared simply by mixing equal volumes of the oil and limewater. The emulsifying agent in this instance is the calcium salt of the free fatty acid which is formed from the combination of two entities.

A

In-Situ Soap Method

40
Q

Four (4) Equipment Used for Emulsification

A
  1. Ultrasonifier
  2. Mechanical Stirrers
  3. Homogenizers
  4. Rotor Stator or Colloid Mill
41
Q

Equipment for emulsions which produce extremely fine particles for moderately viscous emulsions.

A

Ultrasonifier

42
Q

An ideal for slow mixing of finished emulsions which have been prepared by melting of the waxes.

A

Mechanical Stirrers

43
Q

They can produce extremely fine droplets depending on the viscosity and internal tension of the system.

A

Homogenizers

44
Q

It produces very fine particle size and distribution.

A

Rotor Stator or Colloid Mill

45
Q

(T/F): Problems when producing the primary emulsion is that it becomes oily and translucent owing to phase inversion.

A

T

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