Drug release testing methods MCQs With Answer

Introduction: Drug Release Testing Methods MCQs With Answer provides M.Pharm students with a focused, practical collection of multiple-choice questions designed to reinforce understanding of dissolution and release testing principles. This set emphasizes apparatus selection (USP I–IV), sink conditions, sampling strategies, discriminatory power, IVIVC, method validation and QbD considerations. Questions include routine tablet and modified-release systems, semisolids, nanoparticles and flow-through techniques, with attention to common artifacts and statistical tools used for profile comparison. Use these MCQs to test your conceptual depth, prepare for exams, and improve problem-solving skills when developing or interpreting in vitro release studies aligned with regulatory expectations.

Q1. What is the primary objective of drug release (dissolution) testing in pharmaceutical development?

• To predict in vivo performance of a dosage form
• To assess chemical stability during storage
• To determine microbial limits of a product
• To measure particle size distribution

Correct Answer: To predict in vivo performance of a dosage form

Q2. Which USP chapter specifically describes apparatus and procedures for dissolution testing of solid oral dosage forms?

• USP <711> — Dissolution
• USP <51> — Antimicrobial Effectiveness
• USP <61> — Microbial Enumeration
• USP <905> — Uniformity of Dosage Units

Correct Answer: USP <711> — Dissolution

Q3. Which apparatus is commonly referred to as “paddle” in standard dissolution testing?

• USP I — Basket
• USP II — Paddle
• USP III — Reciprocating Cylinder
• USP IV — Flow-Through Cell

Correct Answer: USP II — Paddle

Q4. What defines “sink conditions” in dissolution testing?

• When the dissolved drug concentration remains ≤10% of its saturation solubility
• When the medium volume is equal to the tablet disintegration volume
• When the drug is completely dissolved within 5 minutes
• When the dissolution apparatus runs without sampling

Correct Answer: When the dissolved drug concentration remains ≤10% of its saturation solubility

Q5. Which f2 similarity factor value range indicates that two dissolution profiles are similar?

• f2 between 50 and 100
• f2 less than 20
• f2 between 20 and 40
• f2 greater than 150

Correct Answer: f2 between 50 and 100

Q6. What is meant by a “discriminatory” dissolution method?

• A method able to detect meaningful formulation or manufacturing changes
• A test that always gives 100% release regardless of formulation
• A method that requires no method validation
• A test only usable for immediate-release products

Correct Answer: A method able to detect meaningful formulation or manufacturing changes

Q7. Which USP apparatus is known as the “flow-through cell” and is recommended for low-dose or poorly soluble drugs?

• USP I — Basket
• USP II — Paddle
• USP III — Reciprocating Cylinder
• USP IV — Flow-Through Cell

Correct Answer: USP IV — Flow-Through Cell

Q8. For in vitro release testing of nanoparticle suspensions where maintaining sink and rapid separation are critical, which approach is often preferred?

• Sample-and-separate (centrifugation/filtration) method
• Use of static Franz diffusion cell only
• Measure whole-suspension turbidity without separation
• Use tablet-disintegration apparatus

Correct Answer: Sample-and-separate (centrifugation/filtration) method

Q9. What does a lower Mean Dissolution Time (MDT) indicate about a formulation?

• Faster drug release rate
• Greater variability between units
• More incomplete dissolution
• Longer lag time before release starts

Correct Answer: Faster drug release rate

Q10. Which level of IVIVC represents a point-to-point correlation between in vitro dissolution and in vivo input rate?

• Level A — point-to-point correlation
• Level B — statistical moment comparison
• Level C — single-point correlation
• Level D — no correlation

Correct Answer: Level A — point-to-point correlation

Q11. Which strategy is commonly used to improve sink conditions for poorly soluble drugs during dissolution testing?

• Add surfactants (e.g., SDS) to the dissolution medium
• Decrease the temperature to 25 °C
• Reduce the medium volume to concentrate the sample
• Eliminate agitation entirely

Correct Answer: Add surfactants (e.g., SDS) to the dissolution medium

Q12. Which validation parameter specifically addresses repeatability of dissolution measurements?

• Precision (repeatability)
• Accuracy (trueness)
• Specificity
• System suitability

Correct Answer: Precision (repeatability)

Q13. What is a major advantage of the flow-through (USP IV) cell over the paddle (USP II) for certain products?

• Continuous renewal of medium allows better control for low-dose and poorly soluble drugs
• It is less complex and requires no pumps
• It uses a smaller medium volume than all other methods
• It guarantees sink conditions without method development

Correct Answer: Continuous renewal of medium allows better control for low-dose and poorly soluble drugs

Q14. What common artifact must be evaluated when using dialysis membrane methods for release testing?

• Adsorption or binding of drug to the membrane
• Excessive mechanical shear from paddles
• Contamination from basket wires
• Evaporation due to open cells

Correct Answer: Adsorption or binding of drug to the membrane

Q15. Which dissolution metric quantifies percent difference (dissimilarity) between two profiles?

• f1 (difference factor)
• f2 (similarity factor)
• MDT (mean dissolution time)
• t50% (time to 50% release)

Correct Answer: f1 (difference factor)

Q16. Which kinetic model describes diffusion-controlled release with a square-root-of-time dependence?

• Higuchi model
• Zero-order model
• First-order model
• Korsmeyer–Peppas model with n = 1

Correct Answer: Higuchi model

Q17. In a QbD (Quality by Design) approach to dissolution method development, what is a key activity?

• Identification of critical method parameters and use of design of experiments (DoE)
• Minimizing testing to a single time point
• Using only one dissolution apparatus for all products
• Avoiding robustness studies to speed development

Correct Answer: Identification of critical method parameters and use of design of experiments (DoE)

Q18. Which apparatus or variant is specifically used for in vitro release testing of transdermal patches?

• Paddle-over-disk (transdermal patch testing)
• USP I — Basket for tablets
• Flow-through cell exclusively for tablets
• Reciprocating cylinder for capsules only

Correct Answer: Paddle-over-disk (transdermal patch testing)

Q19. What is the standard temperature required for most dissolution tests to mimic physiological conditions?

• 37 ± 0.5 °C
• 25 ± 2 °C
• 45 ± 1 °C
• 4 ± 1 °C

Correct Answer: 37 ± 0.5 °C

Q20. In a dissolution specification, what does “Q” typically represent?

• The specified percent of drug substance dissolved at a defined time point
• The quantity of excipient per tablet
• The quota of batches to be tested
• The quality score from sensory testing

Correct Answer: The specified percent of drug substance dissolved at a defined time point

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