48 Questions
What is the fraction of Tween 80 used in the emulsion formulation?
0.58
What is the fraction of Span 80 used in the emulsion formulation?
0.42
How much Sorbitan monooleate is required for the emulsion formulation?
2.1 g
How much Polyoxyethylene 20 sorbitan monoleate is required for the emulsion formulation?
2.9 g
What is the purpose of heating the oil-soluble sorbitan monooleate to 75°?
To dissolve it in the oil
Why is the water-soluble polyoxyethylene 20 sorbitan monooleate added to the aqueous phase at 70°?
To prevent it from solidifying
What does the formulator mean by not being restricted to using only the mentioned emulsifying agents?
Other combinations of emulsifying agents can also achieve an HLB of 10.5
Why are various methods employed for emulsion preparation?
To adapt to the nature of components and desired emulsion characteristics
What is the primary indication for Castor Oil Emulsion?
Laxative for constipation
Which type of emulsion are many hand and body lotions for dry skin?
o/w emulsions
What are liniments intended for?
Rubbing on the skin
What does Simethicone Emulsion act as?
Defoaming agent for relief of gastrointestinal gas symptoms
What is the emulsifying agent formed from the combination of olive oil and calcium?
Oleic acid
What equipment is used on a larger scale for emulsion formation?
High-speed impellers
Which process refers to the aggregation or joining of droplets without any change in primary droplet size?
Flocculation
What contributes to the tendency of aggregates of globules to rise to the top or fall to the bottom of an emulsion?
Phase separation
What is the primary purpose of pharmaceutical emulsions?
To enhance the stability of drugs
Which factor plays a significant role in affecting the stability of emulsions?
Particle size of the dispersed phase
What distinguishes microemulsions from macroemulsions?
Microemulsions are optically transparent
What is the primary function of emulsifying agents in pharmaceutical emulsions?
To reduce the interfacial tension between oil and water phases
What is the ratio of surfactant A to surfactant B to achieve a total HLB value of 9.0?
1:2
How is the total HLB value of a mixture of surfactants calculated?
Adding the HLB values of the surfactants
Why may combining two or more emulsifiers be necessary to achieve the required HLB value?
To achieve the desired stability of the emulsion
What is assumed to be an algebraic summation of the HLB for a mixture of surfactants?
$HLB_{total} = HLBA ( X) + HLBB (1-X)$
What is the crucial step to consider prior to emulsion preparation?
Dissolving water-soluble ingredients in the aqueous phase
Why is it important to warm the aqueous phase 2-3°C above the oil phase?
To prevent local crystallization of waxes
Why should alcohol or solutions containing alcohol not be added directly to the primary emulsion?
To prevent precipitation of gums such as acacia
When should substances that might interfere with the stability of the emulsion be added?
After all diluents are added
Why is the Forbes bottle method not suitable for viscous oils?
Viscous oils cannot be thoroughly agitated in the bottle when mixed with the emulsifying agent.
What is the purpose of passing an emulsion through a hand homogenizer?
To reduce the globules of the internal phase to a very small size.
What type of soaps are developed by the In Situ Soap Method?
Calcium soaps and soft soaps.
Why are viscous oils not suitable for the Forbes bottle method?
They cannot be thoroughly agitated in the bottle when mixed with the emulsifying agent.
In emulsion terminology, what is the dispersed phase also known as?
Internal phase
What is the primary role of an emulsifying agent in preparing a stable emulsion?
To prevent the aggregation of droplets
Which type of emulsion can be diluted or extended with water or an aqueous preparation?
Oil-in-Water (o/w) Emulsions
What distinguishes multiple emulsions from macroemulsions?
The presence of more than two immiscible liquids
Why is the dry gum method generally employed when the intended dispersed phase is a mixture of fixed oil and volatile oil?
To increase the emulsion's stability
What is the primary reason for passing an emulsion through a hand homogenizer?
To reduce the particle size of very thick emulsions
What are the two types of soaps developed by the In Situ Soap Method?
Calcium soaps and magnesium soaps
Why is the Forbes bottle method not suited for viscous oils?
Because it cannot thoroughly agitate viscous oils mixed with the emulsifying agent in the bottle
What is the fraction of Polyoxyethylene 20 sorbitan monoleate required for the emulsion formulation?
3.8 g
What is the total HLB value of the mixture of Tween 80 and Span 80 used to produce a physically stable liquid paraffin emulsion?
10.5
Why might combining two or more emulsifiers be necessary to achieve the required HLB value?
To modify the hydrophilic-lipophilic balance
What contributes to the tendency of aggregates of globules to rise to the top or fall to the bottom of an emulsion?
Density difference between the dispersed phase and dispersion medium
Why is it important for o/w emulsions to be easily removed from the skin?
To enhance percutaneous absorption
What is a crucial step required to prevent the separation of phases in pharmaceutical emulsions?
Careful formulation to prevent the separation of phases
Which characteristic makes w/o emulsions more suitable for dry skin?
Resisting drying and removal by contact with water
What is a disadvantage of pharmaceutical emulsions?
Require careful formulation to prevent phase separation
Test your knowledge on emulsions and emulsifying agents in disperse systems. Explore the use of calcium salt of free fatty acid as an emulsifying agent and the large-scale preparation methods for emulsions.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
