MCQ Quiz: Compounding and Quality of Mixing Powders

Welcome, PharmD students, to this MCQ quiz on Compounding and the Quality of Mixing Powders! Pharmaceutical compounding often involves the meticulous mixing of powders to create customized medications. Achieving a homogenous and accurate blend is critical for ensuring dose uniformity and therapeutic efficacy of the final preparation. This quiz will test your understanding of powder mixing techniques like geometric dilution, factors affecting powder blends, equipment used, and essential quality considerations. Let’s delve into the art and science of powder compounding!

1. Which of the following techniques is most appropriate for thoroughly mixing a small quantity of a potent drug with a large quantity of a diluent powder?

• a) Spatulation
• b) Tumbling
• c) Geometric dilution
• d) Levigation

Answer: c) Geometric dilution

2. The process of reducing the particle size of a powder, often using a mortar and pestle, is known as:

• a) Comminution (trituration is a form of this)
• b) Segregation
• c) Eutexia
• d) Hygroscopicity

Answer: a) Comminution (trituration is a form of this)

3. What is the primary purpose of using geometric dilution when mixing powders?

• a) To increase the bulk density of the powder mixture.
• b) To ensure uniform distribution of a small amount of active ingredient throughout a larger amount of diluent.
• c) To reduce the particle size of all ingredients simultaneously.
• d) To increase the flowability of the powder.

Answer: b) To ensure uniform distribution of a small amount of active ingredient throughout a larger amount of diluent.

4. Which of the following factors is LEAST likely to cause segregation (de-mixing) of a powder blend?

• a) Widely different particle sizes of the components.
• b) Significant differences in particle densities.
• c) Uniform particle shape and size for all components.
• d) Excessive vibration during handling or storage.

Answer: c) Uniform particle shape and size for all components.

5. Spatulation is a mixing technique best suited for:

• a) Incorporating large quantities of potent drugs.
• b) Blending small amounts of powders on a tile or paper, especially for eutectic mixtures or powders that liquefy easily.
• c) Achieving very thorough mixing of powders with significantly different densities.
• d) Particle size reduction of hard crystalline powders.

Answer: b) Blending small amounts of powders on a tile or paper, especially for eutectic mixtures or powders that liquefy easily.

6. Trituration, when referring to powder mixing, involves:

• a) Dissolving a powder in a solvent.
• b) Grinding powders together in a mortar with a pestle to reduce particle size and mix them.
• c) Melting powders together.
• d) Passing powders through a sieve.

Answer: b) Grinding powders together in a mortar with a pestle to reduce particle size and mix them.

7. A powder that readily absorbs moisture from the air and may liquefy is described as:

• a) Efflorescent
• b) Hygroscopic
• c) Deliquescent
• d) Eutectic

Answer: c) Deliquescent (Hygroscopic absorbs moisture, deliquescent absorbs enough to liquefy)

8. What is a common piece of equipment used for trituration and mixing of powders in small-scale compounding?

• a) V-blender
• b) Ointment mill
• c) Mortar and pestle
• d) Tablet press

Answer: c) Mortar and pestle

9. “Minimum Weighable Quantity” (MWQ) on a balance is important in compounding to:

• a) Determine the largest amount that can be weighed.
• b) Ensure that the quantity weighed is within an acceptable percentage of error (e.g., ±5%).
• c) Calibrate the balance daily.
• d) Measure liquid volumes accurately.

Answer: b) Ensure that the quantity weighed is within an acceptable percentage of error (e.g., ±5%).

10. If you need to weigh a quantity of drug smaller than the MWQ of your balance, which technique should be employed?

• a) Estimate the weight visually.
• b) Use a balance with a lower sensitivity.
• c) The aliquot method of weighing.
• d) Weigh the drug directly and ignore the MWQ.

Answer: c) The aliquot method of weighing.

11. Which property of powders can significantly affect their flowability and mixing characteristics?

• a) Color
• b) Particle shape and surface texture
• c) Taste
• d) Cost

Answer: b) Particle shape and surface texture

12. When performing geometric dilution, the general procedure involves:

• a) Mixing all ingredients together at once.
• b) Adding the largest quantity ingredient to the smallest quantity ingredient in one step.
• c) Starting with the smallest quantity ingredient and adding an approximately equal volume of the larger quantity ingredient, mixing thoroughly, and repeating until all ingredients are incorporated.
• d) Dissolving all powders in a solvent and then evaporating the solvent.

Answer: c) Starting with the smallest quantity ingredient and adding an approximately equal volume of the larger quantity ingredient, mixing thoroughly, and repeating until all ingredients are incorporated.

13. An efflorescent powder is one that:

• a) Absorbs moisture from the air to become damp.
• b) Releases water of crystallization upon exposure to air, potentially becoming damp or pasty.
• c) Melts at a lower temperature when mixed with another powder.
• d) Has a very fine particle size.

Answer: b) Releases water of crystallization upon exposure to air, potentially becoming damp or pasty.

14. Sieving powders before or during mixing can help to:

• a) Increase the bulk density only.
• b) Ensure a uniform particle size range and break up agglomerates, improving mixing quality.
• c) Increase the hygroscopicity of the powders.
• d) Chemically stabilize the ingredients.

Answer: b) Ensure a uniform particle size range and break up agglomerates, improving mixing quality.

15. Quality control for compounded powders may include visual inspection for:

• a) The correct number of tablets.
• b) Uniformity of color and texture, and absence of clumps.
• c) Proper labeling of the source ingredients only.
• d) The pH of the powder.

Answer: b) Uniformity of color and texture, and absence of clumps.

16. A eutectic mixture occurs when:

• a) Two powders are mixed and the melting point of the mixture is higher than that of individual components.
• b) Two or more substances are mixed and they liquefy at room temperature due to a lowering of their collective melting point.
• c) Powders absorb moisture and become sticky.
• d) Powders segregate due to density differences.

Answer: b) Two or more substances are mixed and they liquefy at room temperature due to a lowering of their collective melting point.

17. To prevent liquefaction of a eutectic mixture when compounding powders, one might:

• a) Triturate them very vigorously together.
• b) Add an absorbent powder (adsorbent diluent) like light magnesium oxide or kaolin before mixing.
• c) Store the powders in a humid environment.
• d) Heat the powders before mixing.

Answer: b) Add an absorbent powder (adsorbent diluent) like light magnesium oxide or kaolin before mixing.

18. The choice of mortar and pestle (e.g., glass vs. Wedgwood vs. porcelain) depends on factors like:

• a) The color of the powders being mixed.
• b) The properties of the substances being compounded (e.g., abrasiveness, staining potential, need for particle size reduction).
• c) The cost of the equipment only.
• d) The personal preference of the pharmacist, with no technical basis.

Answer: b) The properties of the substances being compounded (e.g., abrasiveness, staining potential, need for particle size reduction).

19. Good compounding practice for powders includes:

• a) Using the smallest possible equipment regardless of the quantity.
• b) Ensuring accurate calculations and weighing of all ingredients.
• c) Avoiding any documentation to save time.
• d) Mixing ingredients in any random order.

Answer: b) Ensuring accurate calculations and weighing of all ingredients.

20. When compounding powders that are light and fluffy and tend to float in the air, it is important to:

• a) Mix them rapidly in an open area.
• b) Use appropriate ventilation (e.g., powder containment hood) and wear personal protective equipment (PPE).
• c) Add a dense liquid to weigh them down.
• d) Ignore the floating as it doesn’t affect quality.

Answer: b) Use appropriate ventilation (e.g., powder containment hood) and wear personal protective equipment (PPE).

21. If a compounded powder preparation is intended for reconstitution into a liquid by the patient, what is a critical quality attribute of the powder blend?

• a) It must be very dense.
• b) It must have a very bitter taste.
• c) It must be easily and uniformly dispersible or soluble in the specified vehicle.
• d) It must contain visible color streaks.

Answer: c) It must be easily and uniformly dispersible or soluble in the specified vehicle.

22. Tumbling as a method for mixing powders, often done using a jar or a V-blender, is particularly useful for:

• a) Incorporating very small amounts of active drug.
• b) Mixing powders with very different particle sizes without further size reduction.
• c) Blending granular or free-flowing powders with minimal shear.
• d) Reducing the particle size of cohesive powders.

Answer: c) Blending granular or free-flowing powders with minimal shear.

23. What is the primary reason for the emphasis on achieving content uniformity in compounded powder dosage forms (e.g., divided powders or capsules)?

• a) To make the product look aesthetically pleasing.
• b) To ensure each unit dose contains the correct amount of active pharmaceutical ingredient (API) within acceptable limits.
• c) To reduce the overall weight of the product.
• d) To increase the powder’s flowability.

Answer: b) To ensure each unit dose contains the correct amount of active pharmaceutical ingredient (API) within acceptable limits.

24. Which of the following can improve the flow properties of a powder?

• a) Adding a very fine, cohesive powder.
• b) Increasing the moisture content significantly.
• c) Adding a glidant like colloidal silicon dioxide.
• d) Using particles of very irregular shapes.

Answer: c) Adding a glidant like colloidal silicon dioxide.

25. The term “bulk density” of a powder refers to:

• a) The density of the individual powder particles themselves.
• b) The mass of the powder divided by its total occupied volume, including air spaces between particles.
• c) The powder’s ability to flow.
• d) The powder’s solubility in water.

Answer: b) The mass of the powder divided by its total occupied volume, including air spaces between particles.

26. When mixing powders of different densities, which phenomenon is most likely to occur if not mixed properly or if subjected to vibration?

• a) Eutexia
• b) Deliquescence
• c) Segregation (denser particles settling at the bottom)
• d) Efflorescence

Answer: c) Segregation (denser particles settling at the bottom)

27. A glass mortar and pestle is preferred for mixing powders when:

• a) Significant particle size reduction is required for hard crystals.
• b) Colored or staining substances are involved, due to its non-porous nature and ease of cleaning.
• c) Large volumes of fluffy powders need to be incorporated.
• d) A rough surface is needed for efficient grinding.

Answer: b) Colored or staining substances are involved, due to its non-porous nature and ease of cleaning.

28. Proper documentation for a compounded powder preparation should include:

• a) Only the patient’s name and address.
• b) Master formulation record details, ingredients (lot numbers, expiration dates), quantities weighed, procedures, and compounder’s initials.
• c) Only the final weight of the product.
• d) The pharmacist’s favorite color.

Answer: b) Master formulation record details, ingredients (lot numbers, expiration dates), quantities weighed, procedures, and compounder’s initials.

29. One potential issue with prolonged trituration of some powders is:

• a) It always increases particle size.
• b) It can generate static electricity, making handling difficult.
• c) It decreases the surface area of the powder.
• d) It makes all powders more soluble.

Answer: b) It can generate static electricity, making handling difficult.

30. When choosing a diluent for a potent powder, the diluent should ideally be:

• a) Chemically reactive with the active drug.
• b) Inert, compatible, and have similar particle size/density to the active drug if possible.
• c) A very different color to ensure visible mixing.
• d) Highly hygroscopic.

Answer: b) Inert, compatible, and have similar particle size/density to the active drug if possible.

31. “Pulverization by intervention” is a technique used for:

• a) Mixing two liquids.
• b) Reducing the particle size of gummy, resinous, or hard crystalline substances by dissolving them in a volatile solvent, mixing with a mortar/pestle, and allowing the solvent to evaporate.
• c) Sterilizing powders.
• d) Increasing the bulk density of powders.

Answer: b) Reducing the particle size of gummy, resinous, or hard crystalline substances by dissolving them in a volatile solvent, mixing with a mortar/pestle, and allowing the solvent to evaporate.

32. The angle of repose is a measure of a powder’s:

• a) Solubility
• b) Density
• c) Flowability
• d) Particle size

Answer: c) Flowability

33. A hygroscopic powder is one that:

• a) Releases moisture to the air.
• b) Readily absorbs moisture from the atmosphere.
• c) Has no interaction with atmospheric moisture.
• d) Is insoluble in water.

Answer: b) Readily absorbs moisture from the atmosphere.

34. What is a key safety precaution when compounding with fine powders, especially potent ones?

• a) Using a fan to blow away excess powder.
• b) Avoiding the use of any personal protective equipment (PPE).
• c) Working in a powder containment hood or well-ventilated area, and wearing appropriate PPE like masks and gloves.
• d) Tasting the powder to ensure correct ingredient.

Answer: c) Working in a powder containment hood or well-ventilated area, and wearing appropriate PPE like masks and gloves.

35. If you are mixing 100 mg of active drug with 9.9 g of diluent, what is the first step in geometric dilution?

• a) Mix all of the active drug with all of the diluent at once.
• b) Mix 100 mg of active drug with approximately 100 mg of diluent.
• c) Mix 100 mg of active drug with 5 g of diluent.
• d) Mix all of the diluent with a small portion of the active drug.

Answer: b) Mix 100 mg of active drug with approximately 100 mg of diluent.

36. Beyond-use dates (BUDs) for compounded non-aqueous powder formulations are typically determined based on:

• a) The patient’s request.
• b) USP guidelines or relevant literature, often being no later than 6 months or the earliest expiration date of any active pharmaceutical ingredient (API).
• c) The color of the powder.
• d) Three years from the date of compounding.

Answer: b) USP guidelines or relevant literature, often being no later than 6 months or the earliest expiration date of any active pharmaceutical ingredient (API).

37. The term “levigation” in compounding refers to:

• a) Mixing powders by tumbling.
• b) Reducing particle size and grittiness of a powder by triturating it with a small amount of a liquid (levigating agent) in which the solid is not soluble.
• c) Dissolving a powder completely in a solvent.
• d) Passing powders through a coarse sieve.

Answer: b) Reducing particle size and grittiness of a powder by triturating it with a small amount of a liquid (levigating agent) in which the solid is not soluble.

38. Which problem is most likely if powders with very different particle densities are mixed without proper technique?

• a) Improved flowability
• b) Formation of a eutectic mixture
• c) Stratification or segregation during handling or storage
• d) Increased solubility

Answer: c) Stratification or segregation during handling or storage

39. A primary goal of quality control in powder compounding is to ensure:

• a) The product is the cheapest possible.
• b) The product is accurately prepared, homogenous, and meets all specifications for quality and purity.
• c) The product has the longest possible beyond-use date.
• d) The product looks identical to a manufactured version.

Answer: b) The product is accurately prepared, homogenous, and meets all specifications for quality and purity.

40. When using a spatula for mixing small amounts of powders (spatulation), the primary mixing mechanism is:

• a) High shear forces.
• b) Convective mixing by lifting and moving portions of the powder.
• c) Diffusion of particles.
• d) Particle size reduction.

Answer: b) Convective mixing by lifting and moving portions of the powder.

41. The percentage error in weighing is calculated as:

• a) (Actual weight / Desired weight) × 100%
• b) (|Desired weight – Actual weight| / Actual weight) × 100%
• c) (|Error in weighing| / Quantity desired) × 100%
• d) (Sensitivity of balance / Quantity weighed) × 100%

Answer: c) (|Error in weighing| / Quantity desired) × 100% (More generally, (Absolute Error / True Value) * 100, where absolute error is |measured – true|). Or relating to MWQ, Error = (Sensitivity / Quantity Weighed) * 100.

42. What is a “diluent” in the context of powder compounding?

• a) A substance that increases the potency of the active drug.
• b) An inert substance added to a formulation to increase bulk or create the desired consistency.
• c) A liquid used to dissolve powders.
• d) A substance that causes powders to liquefy.

Answer: b) An inert substance added to a formulation to increase bulk or create the desired consistency.

43. Using a powder that has passed its expiration date in a compounded preparation is:

• a) Acceptable if it looks normal.
• b) Not recommended as its potency and stability may be compromised.
• c) Allowed if mixed with fresh powder.
• d) Only an issue for potent drugs.

Answer: b) Not recommended as its potency and stability may be compromised.

44. The choice of sieve mesh size during powder processing influences the:

• a) Chemical stability of the powder.
• b) Final particle size range of the sieved powder.
• c) Density of the powder.
• d) Solubility of the powder.

Answer: b) Final particle size range of the sieved powder.

45. One method to assess the homogeneity of a powder mixture in a quality control setting (though not typically in routine community pharmacy compounding) could involve:

• a) Tasting the powder.
• b) Taking samples from different parts of the blend and assaying for active ingredient content.
• c) Checking the pH of the powder.
• d) Measuring the angle of repose only.

Answer: b) Taking samples from different parts of the blend and assaying for active ingredient content.

46. Particle characteristics such as being very fine and light can make powders:

• a) Easier to weigh accurately.
• b) More prone to dusting and difficult to handle.
• c) Less likely to segregate.
• d) More dense.

Answer: b) More prone to dusting and difficult to handle.

47. For powders intended to be packed into capsules, good flowability is important to ensure:

• a) The capsules dissolve quickly.
• b) Uniform filling of the capsule shells and consistent weight.
• c) The powder tastes better.
• d) The powder is sterile.

Answer: b) Uniform filling of the capsule shells and consistent weight.

48. Before compounding any powder preparation, the pharmacist must first:

• a) Weigh all ingredients together.
• b) Consult the patient about their color preference.
• c) Review the prescription or formulation, perform necessary calculations, and ensure all equipment is clean and appropriate.
• d) Pre-mix all diluents.

Answer: c) Review the prescription or formulation, perform necessary calculations, and ensure all equipment is clean and appropriate.

49. When recording the compounding process, it is crucial to note the lot numbers of the ingredients used primarily for:

• a) Inventory management.
• b) Traceability in case of a recall or problem with a specific batch of ingredient.
• c) Calculating the cost of the compound.
• d) Determining the powder’s flow characteristics.

Answer: b) Traceability in case of a recall or problem with a specific batch of ingredient.

50. The overall quality of a compounded powder mixture directly impacts the ________ of the final dosage form prepared from it.

• a) Color only
• b) Safety and efficacy, particularly dose uniformity
• c) Storage temperature requirements only
• d) Pharmacist’s workload

Answer: b) Safety and efficacy, particularly dose uniformity