PTCB Certified Pharmacy Technician (PTCE)MedicationsMedium
A pharmacy technician is preparing to compound an emulsion. Which of the following is the primary purpose of an emulsifying agent in this preparation?
- ATo dissolve the solid drug particles
- BTo increase the viscosity of the mixture
- CTo adjust the pH of the final product
- DTo prevent the separation of immiscible liquids
Show answer & explanationAnswer & explanation
Correct answer: D. To prevent the separation of immiscible liquids
Emulsions are mixtures of two immiscible liquids (e.g., oil and water). An emulsifying agent (emulsifier) stabilizes the emulsion by reducing the interfacial tension between the two phases, preventing them from separating over time.
Why the other options are wrong
- A. Dissolving solid particles is the role of a solvent, not an emulsifying agent.
- B. While some emulsifiers can affect viscosity, their primary role is not viscosity modification.
- C. pH adjustment is done with buffering agents, not primarily with emulsifying agents.
Emulsifying Agent
A substance that helps to stabilize an emulsion by forming a protective film around the dispersed droplets and preventing their coalescence.
- Used in emulsions (oil-in-water or water-in-oil).
- Reduces interfacial tension between immiscible liquids.
- Examples include acacia, tragacanth, Tween, Span.
Memory trick: Oil and Water Won't Mix, Unless an Emulsifier Sticks!