Consolidation and compaction profiles MCQs With Answer

Consolidation and compaction profiles MCQs With Answer

by

Introduction

Consolidation and compaction profiles are central to understanding how powders transform into robust tablets during pharmaceutical manufacturing. For M. Pharm students, mastering these profiles helps in diagnosing formulation issues, selecting excipients, and optimizing press parameters. This quiz focuses on key analytical tools—Heckel, Kawakita, and Ryshkewitch–Duckworth analyses; the compaction triangle (compressibility, compactibility, tabletability); and instrumented press outputs such as force–displacement and energy analysis. You will also encounter concepts like dwell time, elastic recovery, die-wall friction, and the impact of lubricants on bonding. Each MCQ is designed to test deeper comprehension and application, enabling you to interpret compaction data scientifically and make evidence-based decisions in formulation and process development.

Q1. In the compaction “triangle,” which profile plots tensile strength as a function of compaction pressure to compare materials’ ability to generate strength under a given load?

  • Compressibility profile
  • Compactibility profile
  • Tabletability profile
  • Lubricity profile

Correct Answer: Tabletability profile

Q2. In the Heckel analysis, the slope (K) of the linear region relates to plasticity. Which statement is correct?

  • The reciprocal of the slope (1/K) gives the mean yield pressure (Py)
  • The slope itself equals the mean yield pressure (Py)
  • The intercept gives the mean yield pressure (Py)
  • The negative slope gives the Kawakita pressure (Pk)

Correct Answer: The reciprocal of the slope (1/K) gives the mean yield pressure (Py)

Q3. In the Kawakita equation, P/C = P/a + 1/(ab), what does the parameter “a” represent?

  • The porosity at maximum applied pressure
  • The maximal fractional volume reduction (initial porosity)
  • The pressure needed to overcome die-wall friction
  • The slope of the Heckel plot

Correct Answer: The maximal fractional volume reduction (initial porosity)

Q4. Which setup is required to obtain full force–displacement compaction profiles (loading/unloading) for powders and tablets?

  • Friabilator with hardness tester
  • Bulk/tapped density cylinder
  • Instrumented compaction press or compaction simulator
  • Dissolution apparatus II

Correct Answer: Instrumented compaction press or compaction simulator

Q5. Which change(s) will increase dwell time during tableting?

  • Increase turret speed
  • Decrease punch head flat length
  • Increase punch head flat length and/or decrease turret speed
  • Use a deeper die

Correct Answer: Increase punch head flat length and/or decrease turret speed

Q6. A material exhibits a low mean yield pressure (Py) from Heckel analysis. What does this imply?

  • It resists plastic deformation and consolidates by brittle fracture
  • It readily undergoes plastic deformation under pressure
  • It cannot be compressed at high speeds
  • It has high inherent porosity at all pressures

Correct Answer: It readily undergoes plastic deformation under pressure

Q7. For cross-formulation comparison of mechanical strength across tablet sizes, which metric is most appropriate?

  • Breaking force (crushing strength) alone
  • Tensile strength normalized by geometry (e.g., σt)
  • Friability (%)
  • Disintegration time

Correct Answer: Tensile strength normalized by geometry (e.g., σt)

Q8. Out-of-die elastic recovery is best quantified by which measurement?

  • Reduction in porosity at maximum force
  • Increase in tablet thickness after ejection relative to in-die thickness
  • Decrease in ejection force with more lubricant
  • Increase in turret speed at constant force

Correct Answer: Increase in tablet thickness after ejection relative to in-die thickness

Q9. Prolonged blending with magnesium stearate typically has what combined effect on compaction behavior?

  • Increases tablet tensile strength and increases ejection force
  • Decreases tablet tensile strength at a given density and reduces ejection force
  • No effect on bonding or ejection
  • Increases compactibility without changing ejection

Correct Answer: Decreases tablet tensile strength at a given density and reduces ejection force

Q10. The Ryshkewitch–Duckworth relation (σt = σ0·e−kε) is often linearized as ln σt versus porosity (ε). What does the slope represent?

  • Positive bonding coefficient (k)
  • Negative bonding sensitivity coefficient (−k)
  • Mean yield pressure (Py)
  • Kawakita pressure (Pk)

Correct Answer: Negative bonding sensitivity coefficient (−k)

Q11. A high brittle fracture index (BFI) indicates what about a material’s compaction behavior?

  • Dominant plastic deformation with low capping risk
  • High elastic recovery but strong interparticulate bonds
  • Pronounced brittle fracture and higher tendency for capping/lamination
  • Viscous flow with minimal density gradients

Correct Answer: Pronounced brittle fracture and higher tendency for capping/lamination

Q12. In a force–displacement profile, which area corresponds to plastic work of compaction?

  • Area under the unloading curve
  • Area under the loading curve only
  • Hysteresis area between loading and unloading curves
  • Area above maximum force

Correct Answer: Hysteresis area between loading and unloading curves

Q13. Precompression in a rotary press primarily helps to:

  • Increase ejection force
  • Remove entrapped air and reduce capping/lamination risk
  • Increase elastic recovery
  • Decrease tablet tensile strength

Correct Answer: Remove entrapped air and reduce capping/lamination risk

Q14. Which statement is true regarding in-die vs out-of-die measurements during compaction?

  • Out-of-die solid fraction at room conditions is typically higher than in-die at peak force
  • In-die measurements capture viscoelastic effects and are generally higher than out-of-die due to elastic recovery after unloading
  • In-die and out-of-die solid fractions are identical at all speeds
  • Out-of-die data cannot be used to calculate tensile strength

Correct Answer: In-die measurements capture viscoelastic effects and are generally higher than out-of-die due to elastic recovery after unloading

Q15. In Kawakita analysis, what is the physical meaning of 1/b (often termed Pk)?

  • Pressure at which porosity is zero
  • Pressure required to attain half of the total possible volume reduction
  • Pressure at the onset of elastic recovery
  • Pressure where Heckel plot becomes non-linear

Correct Answer: Pressure required to attain half of the total possible volume reduction

Q16. Increased die-wall friction during compaction most directly leads to:

  • Lower ejection work and uniform density
  • Greater density gradients and higher ejection work
  • No change in force–displacement hysteresis
  • Higher tensile strength at the same density

Correct Answer: Greater density gradients and higher ejection work

Q17. Which profile best isolates material bonding performance from densification, enabling comparison across different press settings?

  • Compressibility (solid fraction vs pressure)
  • Compactibility (tensile strength vs solid fraction)
  • Tabletability (tensile strength vs pressure)
  • Ejection profile (force vs punch travel)

Correct Answer: Compactibility (tensile strength vs solid fraction)

Q18. Which excipient is most likely to exhibit a low mean yield pressure (high plasticity) in Heckel analysis?

  • Microcrystalline cellulose
  • Dicalcium phosphate dihydrate
  • Lactose monohydrate (spray-dried)
  • Mannitol (granular)

Correct Answer: Microcrystalline cellulose

Q19. When lubricant level is increased but densification behavior remains similar, which profile most clearly reveals weakened bonding?

  • Compressibility profile
  • Compactibility profile
  • Ejection work profile
  • Porosity–time profile

Correct Answer: Compactibility profile

Q20. Which set correctly defines the “compaction triangle” used to characterize powder performance for tablet manufacture?

  • Flowability, hygroscopicity, lubricity
  • Compressibility, compactibility, tabletability
  • Friability, disintegration, dissolution
  • Porosity, viscosity, permeability

Correct Answer: Compressibility, compactibility, tabletability

Leave a Comment