Pilot plant scale-up concepts MCQs With Answer

Pilot plant scale-up concepts MCQs With Answer

This quiz collection is designed for M.Pharm students focusing on pilot plant scale-up and technology transfer. It covers fundamental principles and practical considerations used when taking formulations and processes from laboratory to pilot and manufacturing scales. Topics include geometric and dynamic similarity, dimensionless numbers (Reynolds, Froude, Péclet), mixing and heat transfer scale-up rules, mass transfer (kLa), equipment selection, process validation, risk mitigation, and common scale-up pitfalls in granulation, drying, coating and sterile operations. These questions emphasize mechanistic understanding and decision-making required in real-world product development and technology transfer activities.

Q1. In scaling up a stirred tank reactor while maintaining geometric similarity, which parameter must be preserved to maintain similar mixing performance related to viscous dominated flows?

• Tip speed
• Power per unit volume (P/V)
• Reynolds number
• Froude number

Correct Answer: Reynolds number

Q2. For scale-up where gravity-driven free-surface phenomena (e.g., vortexing, surface aeration) are critical, which dimensionless number is most appropriate to match between scales?

• Péclet number
• Reynolds number
• Froude number
• Prandtl number

Correct Answer: Froude number

Q3. Which scale-up rule is most commonly applied when heat transfer (as opposed to mixing) is the critical performance attribute?

• Maintain constant tip speed
• Maintain constant power per unit volume (P/V)
• Maintain constant surface area-to-volume ratio (A/V)
• Maintain constant Reynolds number

Correct Answer: Maintain constant surface area-to-volume ratio (A/V)

Q4. The volumetric mass transfer coefficient (kLa) is vital for aerobic fermentation scale-up. Which approach is commonly used to preserve oxygen transfer when scaling up?

• Keep geometric similarity and allow kLa to vary
• Match power input per unit volume (P/V) to achieve similar kLa
• Match tip speed only
• Match reactor height only

Correct Answer: Match power input per unit volume (P/V) to achieve similar kLa

Q5. When scale-up from lab to pilot shows longer mixing times, what is the most likely cause?

• Increased Péclet number
• Lower relative agitator speed and decreased turbulent intensity
• Higher oxygen solubility at larger volume
• Decrease in solution viscosity

Correct Answer: Lower relative agitator speed and decreased turbulent intensity

Q6. Which of the following is a primary risk to consider specifically during scale-up of a granulation process?

• Change in tablet dissolution medium composition
• Variation in spray nozzle atomization and binder distribution
• Inaccurate HPLC method transfer
• Different capsule color fading

Correct Answer: Variation in spray nozzle atomization and binder distribution

Q7. In equipment scale-up, “scale-up by maintaining constant tip speed” is most appropriate when which effect dominates?

• Surface-driven gravitational effects
• Shear-sensitive processes where surface velocity governs phenomena
• Heat transfer limited systems
• Mass transfer controlled by bubble size in sparged reactors

Correct Answer: Shear-sensitive processes where surface velocity governs phenomena

Q8. Which technique is commonly used to quantify residence time distribution (RTD) differences between lab and pilot reactors during scale-up?

• Tracer pulse or step input with conductivity or UV monitoring
• Measuring bulk temperature only
• Using theoretical mixing length without experiments
• Visual observation of vortex formation

Correct Answer: Tracer pulse or step input with conductivity or UV monitoring

Q9. During scale-up of a heat-sensitive API crystallization, what control strategy helps maintain similar nucleation and crystal growth rates?

• Matching only agitator diameter
• Controlling supersaturation profiles via cooling and feed rates
• Using identical probe brand across scales
• Increasing batch volume without process control changes

Correct Answer: Controlling supersaturation profiles via cooling and feed rates

Q10. Which dimensionless group relates convective to diffusive heat transfer and is important when scaling thermal processes?

• Péclet number
• Prandtl number
• Sherwood number
• Damköhler number

Correct Answer: Péclet number

Q11. In spray drying scale-up, which parameter most directly affects droplet residence time and drying efficiency?

• Feed pH
• Inlet air temperature and droplet size distribution
• Tablet compression force
• UV lamp intensity in coating chamber

Correct Answer: Inlet air temperature and droplet size distribution

Q12. For scale-up of sterile filling, what is a critical additional concern compared with non-sterile operations?

• Maintaining identical color of equipment
• Maintaining aseptic conditions, validated transfer and closed-system handling
• Using the same lot of excipients
• Scaling of packaging artwork

Correct Answer: Maintaining aseptic conditions, validated transfer and closed-system handling

Q13. Which statement about power number (Np) and scale-up is correct?

• Power number is irrelevant for mixing scale-up
• Power number correlates agitator geometry and flow regime; Np helps relate power, speed, and size
• Power number only applies to non-Newtonian fluids
• Power number is constant for all agitator speeds

Correct Answer: Power number correlates agitator geometry and flow regime; Np helps relate power, speed, and size

Q14. When scaling up a drying process (tray or fluid bed), which scale effect frequently causes longer drying times at pilot scale?

• Higher ambient humidity at pilot plant
• Reduced air-to-bed contact efficiency and larger thermal mass
• Faster port filling
• Change in API polymorph only

Correct Answer: Reduced air-to-bed contact efficiency and larger thermal mass

Q15. Which approach is best to de-risk scale-up and ensure reproducibility across scales during technology transfer?

• Rely solely on supplier specifications
• Conduct systematic design of experiments (DoE) and critical process parameter mapping
• Skip pilot runs and move directly to full scale
• Change multiple process variables simultaneously at full scale

Correct Answer: Conduct systematic design of experiments (DoE) and critical process parameter mapping

Q16. In scale-up of a continuous process, which metric is central to ensuring similar conversion and selectivity when residence time distribution cannot be identically matched?

• Maintaining identical vessel color
• Maintaining equivalent space-time (τ) or mean residence time
• Matching only feedstock particle size
• Matching batch numbering conventions

Correct Answer: Maintaining equivalent space-time (τ) or mean residence time

Q17. Which factor often causes non-linearity when extrapolating mixing energy from lab to large tanks?

• Linearly scaled impeller shaft material
• Transition from laminar to turbulent regime and changes in flow patterns
• Using the same compressor brand
• Identical impeller color

Correct Answer: Transition from laminar to turbulent regime and changes in flow patterns

Q18. During scale-up, validation protocols require defining acceptable ranges for critical quality attributes (CQAs). Which of the following is a CQA influenced by scale-up of a tablet coating process?

• Coating thickness and uniformity affecting dissolution
• Batch numbering format
• Supplier invoice date
• Tablet imprint font size

Correct Answer: Coating thickness and uniformity affecting dissolution

Q19. Which parameter is most useful for predicting power draw of an agitated vessel when using dimensionless correlations during scale-up?

• Reactor wall color
• Power number (Np) combined with fluid density, impeller diameter and rotational speed
• Batch record template
• Operator experience in unrelated processes

Correct Answer: Power number (Np) combined with fluid density, impeller diameter and rotational speed

Q20. When performing scale-down studies to troubleshoot manufacturing issues, what is the main goal?

• To exactly copy manufacturing batch records verbatim
• To create a small-scale model that replicates the key hydrodynamic, thermal and compositional stresses responsible for the observed issue
• To reduce costs by changing formulations arbitrarily
• To test only different packaging formats

Correct Answer: To create a small-scale model that replicates the key hydrodynamic, thermal and compositional stresses responsible for the observed issue

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