29 Questions
Emulsions consist of at least two immiscible liquid phases, one of which is dispersed as globules in the other liquid phase.
True
Emulsions are stabilized by the presence of an emulsifying agent to prevent coalescence of the dispersed phase.
True
Oral formulation of medicinal emulsions are usually of the o/w type.
True
Using the naked eye, it is easy to differentiate between o/w and w/o emulsions.
False
True or false: Creaming is an irreversible process?
False
True or false: Breaking of the internal phase separation is called breaking of the emulsion?
True
True or false: Breaking leads to the destruction of the film surrounding the particles and coalescence of oil globules?
True
True or false: Particle size and viscosity correlate with breaking?
False
True or false: A phase-volume ratio of 50:50 results in the most stable emulsion?
True
True or false: Preservation of emulsions is important to prevent physical phase separation, discoloration, and changes in properties?
True
True or false: Preservatives must be able to partition into the water phase and penetrate the bacteria's membrane?
True
True or false: Gels are useful in different administrations and can only be clear?
False
True or false: Gels can be one-phase or two-phase systems, depending on the presence of discrete particles?
True
True or false: Syneresis is the enlarging of a gel with liquid uptake?
False
True or false: Ointments are classified into oleaginous bases, water-removable bases, and water-soluble bases?
True
True or false: The selection of the appropriate ointment base depends on factors such as drug release rate, drug absorption, occlusion of moisture, stability, and desired characteristics?
True
True or false: Dye solubility test can determine the type of emulsion based on the behavior of water- or oil-soluble dyes.
True
True or false: Conductivity test can distinguish between O/W and W/O emulsions based on the ability to carry an electrical current.
True
True or false: Dilution test can determine the type of emulsion by observing how it separates or distributes when diluted with water or oil.
True
True or false: Emulsions are thermodynamically stable and tend to separate into two layers to reduce surface area.
False
True or false: Emulsifying agents are used to promote coalescence and separation of emulsions.
False
True or false: Surface active agents (SAA) are emulsifying agents that reduce interfacial tension and form a monolayer at the oil-water interface, preventing coalescence.
True
True or false: Different SAA are used for O/W and W/O emulsions, with hydrophobic barriers being more effective in O/W emulsions.
False
True or false: HLB (hydrophilic-lipophilic balance) is a scale used to measure the balance between polar and nonpolar properties of surfactants, influencing the emulsion type.
True
True or false: Antifoaming pharmaceuticals, like simethicone, increase the surface tension of gas bubbles to prevent bubble formation.
False
True or false: Different types of SAA (anionic, cationic, nonionic) have similar applications and properties.
False
True or false: A combination of emulsifiers is used in practice, with hydrophilic emulsifying agents for the aqueous phase and hydrophobic emulsifying agents for the oil phase.
True
True or false: Hydrophilic colloids form a multi-molecular film that promotes coalescence and can affect the viscosity of the emulsion.
False
True or false: Finely divided solid particles form a particulate film at the interface and can stabilize emulsions by wetting to the same degree by oil and water.
False
Study Notes
Emulsion Formation and Stability
- Dye solubility test can determine the type of emulsion (O/W or W/O) based on the behavior of water- or oil-soluble dyes.
- Conductivity test can distinguish between O/W and W/O emulsions based on the ability to carry an electrical current.
- Dilution test can determine the type of emulsion by observing how it separates or distributes when diluted with water or oil.
- The theory of emulsification explains that emulsions are thermodynamically unstable and tend to separate into two layers to reduce surface area.
- Emulsifying agents, such as surface active agents (SAA), hydrophilic colloids, and finely divided solid particles, are used to prevent coalescence and separation of emulsions.
- SAA are emulsifying agents that reduce interfacial tension and form a monolayer at the oil-water interface, preventing coalescence.
- Different SAA are used for O/W and W/O emulsions, with hydrophobic barriers being more effective in W/O emulsions.
- HLB (hydrophilic-lipophilic balance) is a scale used to measure the balance between polar and nonpolar properties of surfactants, influencing the emulsion type.
- Antifoaming pharmaceuticals, like simethicone, reduce the surface tension of gas bubbles to prevent bubble formation.
- Different types of SAA (anionic, cationic, nonionic) have different applications and properties.
- A combination of emulsifiers is used in practice, with hydrophilic emulsifying agents for the aqueous phase and hydrophobic emulsifying agents for the oil phase.
- Hydrophilic colloids form a multi-molecular film that resists coalescence and can affect the viscosity of the emulsion.
- Finely divided solid particles form a particulate film at the interface and can stabilize emulsions by wetting to different degrees by oil and water.
Test your knowledge on emulsion formation and stability with this quiz! Learn about different tests to determine the type of emulsion, the theory of emulsification, the role of emulsifying agents, the importance of HLB, and more. Discover how various factors affect emulsion stability and how different types of emulsifiers are used. Challenge yourself and deepen your understanding of emulsion science!
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