Dissolution Testing – Compendial & Alternative MCQs With Answer

Dissolution Testing – Compendial & Alternative MCQs With Answer

This quiz set is designed for M.Pharm students studying MIP 201T – Advanced Biopharmaceutics & Pharmacokinetics. It focuses on compendial dissolution testing principles, commonly used USP apparatus, method development and validation, discriminating power, and alternative/biorelevant approaches for poorly soluble or modified‑release formulations. Questions integrate fundamental theory (e.g., Noyes‑Whitney, sink conditions), practical aspects (sampling, filters, coning, hydrodynamics), and regulatory expectations (similarity factor, IVIVC). Use these MCQs to deepen conceptual understanding, prepare for exams, and practice applying knowledge to choose appropriate apparatus, media, and validation strategies for routine quality control and advanced biopharmaceutic studies.

Q1. Which statement best defines “sink conditions” in dissolution testing?

• The dissolution medium volume should be exactly equal to the tablet’s volume
• The concentration of drug in the medium should be less than three times its solubility
• The dissolution medium should maintain drug concentration well below saturation, typically at least three times the solubility
• The medium must be supersaturated to ensure rapid dissolution

Correct Answer: The dissolution medium should maintain drug concentration well below saturation, typically at least three times the solubility

Q2. Which USP apparatus is described as a flow‑through cell commonly used for poorly soluble and sustained‑release formulations?

• Basket apparatus (Apparatus I)
• Paddle apparatus (Apparatus II)
• Reciprocating cylinder (Apparatus III)
• Flow‑through cell (Apparatus IV)

Correct Answer: Flow‑through cell (Apparatus IV)

Q3. Which factor most directly reduces the formation of coning around a tablet during paddle (Apparatus II) dissolution testing?

• Lowering the medium temperature to 25 °C
• Increasing paddle speed to enhance hydrodynamic shear
• Using a smaller dissolution vessel volume
• Replacing the paddle with a basket

Correct Answer: Increasing paddle speed to enhance hydrodynamic shear

Q4. The Noyes‑Whitney equation indicates that the dissolution rate is directly proportional to which of the following?

• Cumulative amount dissolved only
• Surface area of the drug and the concentration gradient (Cs − C)
• Diffusion coefficient alone
• Tablet hardness only

Correct Answer: Surface area of the drug and the concentration gradient (Cs − C)

Q5. Which is the recommended dissolution test temperature for oral dosage forms to simulate physiological conditions?

• 25 ± 2 °C
• 30 ± 0.5 °C
• 37 ± 0.5 °C
• 45 ± 1 °C

Correct Answer: 37 ± 0.5 °C

Q6. For assessing similarity between two dissolution profiles using the model‑independent similarity factor (f2), what f2 range generally indicates profiles are similar?

• f2 < 30
• f2 between 30 and 50
• f2 between 50 and 100
• f2 > 100

Correct Answer: f2 between 50 and 100

Q7. Which medium is considered a biorelevant simulated intestinal fluid for fasted conditions often used in alternative dissolution testing?

• pH 1.2 simulated gastric fluid
• FaSSIF (Fasted State Simulated Intestinal Fluid)
• 0.1 N HCl only
• Deionized water

Correct Answer: FaSSIF (Fasted State Simulated Intestinal Fluid)

Q8. What is the primary purpose of method discrimination in dissolution method development?

• To ensure the apparatus runs at maximum speed
• To detect formulation or manufacturing changes that affect release
• To make the method as insensitive as possible to minor differences
• To remove the need for analytical validation

Correct Answer: To detect formulation or manufacturing changes that affect release

Q9. When sampling dissolution medium during testing, which practice is recommended to maintain test conditions?

• Remove sample volume and do not replace it
• Replace sampled volume with fresh prewarmed medium
• Cool replacement medium to room temperature before adding
• Replace sampled volume with an equal volume of solvent (e.g., methanol) regardless of temperature

Correct Answer: Replace sampled volume with fresh prewarmed medium

Q10. Which filter pore size is commonly used to clarify dissolution samples before HPLC analysis in routine QC?

• 10 µm
• 5 µm
• 0.45 µm
• 0.01 µm

Correct Answer: 0.45 µm

Q11. Intrinsic dissolution rate (IDR) is most appropriately measured using which of the following approaches?

• Compressed powder poured into paddle apparatus
• Rotating disk of compacted drug with measured surface area
• Dissolution of whole tablet in sink conditions without area control
• Flow injection analysis without medium

Correct Answer: Rotating disk of compacted drug with measured surface area

Q12. Which dissolution profile characteristic indicates a highly discriminatory method during formulation screening?

• All formulations give identical release at every time point
• Small formulation changes produce measurable differences in release profiles
• The method yields very noisy data with high variability
• Results are insensitive to agitation speed

Correct Answer: Small formulation changes produce measurable differences in release profiles

Q13. Level A IVIVC refers to which type of correlation between in vitro and in vivo data?

• Single point correlation of AUC only
• Rank order correlation without time mapping
• Point‑to‑point correlation of the entire in vitro dissolution and in vivo input rate
• Qualitative similarity assessment

Correct Answer: Point‑to‑point correlation of the entire in vitro dissolution and in vivo input rate

Q14. Which parameter is NOT typically part of dissolution method validation attributes required for regulatory acceptance?

• Specificity/selectivity
• Precision and repeatability
• Robustness and discriminatory power
• Color of the dissolution vessel

Correct Answer: Color of the dissolution vessel

Q15. For a poorly soluble BCS Class II drug, which alternative dissolution strategy often improves in vitro–in vivo relevance?

• Use of plain water at 25 °C
• Use of biorelevant media containing bile salts (e.g., FaSSIF/FeSSIF) or biphasic dissolution systems
• Elimination of all surfactants to reduce dissolution
• Always using only USP apparatus I regardless of formulation

Correct Answer: Use of biorelevant media containing bile salts (e.g., FaSSIF/FeSSIF) or biphasic dissolution systems

Q16. Which hydrodynamic factor most affects the reproducibility of dissolution testing in paddle apparatus?

• Paddle color
• Paddle immersion depth and alignment relative to vessel center
• Concentration of dissolved API only
• Ambient humidity outside the apparatus

Correct Answer: Paddle immersion depth and alignment relative to vessel center

Q17. A dissolution method that is described as “discriminatory” should be able to:

• Mask differences between batches
• Detect meaningful differences caused by critical material attributes or process parameters
• Produce identical profiles for generic and reference products
• Only work at one very specific speed and medium without justification

Correct Answer: Detect meaningful differences caused by critical material attributes or process parameters

Q18. When developing a dissolution method for extended‑release tablets, which sampling schedule concept is most appropriate?

• Only sample at one terminal time point
• Collect multiple time points that characterize the full release curve, including early, mid and late phases
• Sample exclusively during the first 5 minutes
• Vary sampling intervals randomly between runs

Correct Answer: Collect multiple time points that characterize the full release curve, including early, mid and late phases

Q19. Which of the following best describes a biphasic dissolution system?

• A single aqueous phase maintained at pH 7
• A system with an aqueous phase and an immiscible organic phase used to simulate absorption and maintain sink
• Two identically composed aqueous phases to double the volume
• A test run with two different paddles sequentially

Correct Answer: A system with an aqueous phase and an immiscible organic phase used to simulate absorption and maintain sink

Q20. Which corrective action is appropriate if a tablet in a paddle test consistently adheres to the vessel bottom causing variable release?

• Decrease the medium temperature to slow dissolution
• Increase paddle speed, verify vessel alignment, or use a sinker if adhesion persists
• Change the analytical method to one with lower sensitivity
• Ignore the variability if mean release meets specification

Correct Answer: Increase paddle speed, verify vessel alignment, or use a sinker if adhesion persists

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