Alternative dissolution testing methods MCQs With Answer

Introduction

This quiz collection focuses on alternative dissolution testing methods relevant to M.Pharm students studying Modern Bio-Analytical Techniques (MPA 202T). It covers advanced in vitro approaches beyond conventional paddle and basket tests — including flow-through cells, dialysis methods, biphasic systems, dissolution–permeation setups, microfluidic and imaging techniques, and biorelevant media use. Questions emphasize the principles, applications, advantages, and limitations of these methods, plus their role in IVIVC and regulatory considerations. The set is designed to deepen conceptual understanding and practical decision-making for formulation development and bioanalysis, helping students evaluate which alternative dissolution technique best fits different dosage forms and research objectives.

Q1. What best defines an “alternative dissolution testing method” in modern pharmaceutical analysis?

• Any dissolution test that uses standard USP apparatus under sink conditions
• In vitro techniques that deviate from conventional paddle/basket to better mimic in vivo conditions, handle challenging formulations, or provide enhanced discrimination
• Only methods using imaging tools like MRI or Raman for solid dosage analysis
• Any test performed exclusively with biorelevant simulated gastric fluids

Correct Answer: In vitro techniques that deviate from conventional paddle/basket to better mimic in vivo conditions, handle challenging formulations, or provide enhanced discrimination

Q2. Which feature makes the USP Apparatus 4 (flow-through cell) particularly useful as an alternative dissolution method?

• It always uses extremely large media volumes to ensure sink conditions
• Its dynamic flow allows continuous fresh medium, controlled hydrodynamics, and suitability for poorly soluble or erodible formulations
• It is limited to immediate release tablets only
• It requires no analytical detection because dissolution is inferred from pressure changes

Correct Answer: Its dynamic flow allows continuous fresh medium, controlled hydrodynamics, and suitability for poorly soluble or erodible formulations

Q3. For nanosuspensions and colloidal systems, which alternative dissolution approach is commonly used to separate dissolution from diffusion effects?

• Paddle apparatus at high agitation speed
• Dialysis-based methods (e.g., reverse dialysis sac or membrane diffusion)
• Biphasic dissolution with an oil layer only
• Simple visual turbidity measurement without separation

Correct Answer: Dialysis-based methods (e.g., reverse dialysis sac or membrane diffusion)

Q4. Biphasic dissolution systems are primarily used to:

• Maintain sink by using very large aqueous volumes only
• Simulate simultaneous dissolution and partitioning into an organic phase to mimic absorption of poorly soluble drugs
• Replace HPLC for quantification of drug concentration
• Measure tablet mechanical strength during dissolution

Correct Answer: Simulate simultaneous dissolution and partitioning into an organic phase to mimic absorption of poorly soluble drugs

Q5. A dissolution–permeation (D/P) system adds which key feature compared to standard dissolution tests?

• Quantitative imaging of solid-state changes only
• Incorporation of a permeation barrier to measure drug appearance on the receiver side, linking dissolution to membrane permeation
• Elimination of the need for analytical quantification
• Use of static medium without sampling

Correct Answer: Incorporation of a permeation barrier to measure drug appearance on the receiver side, linking dissolution to membrane permeation

Q6. Which in situ spectroscopic technique provides real-time concentration profiles near the dissolving surface and is valuable for mechanistic dissolution studies?

• Offline HPLC after filtration
• Fiber-optic UV/visible imaging (UV imaging)
• Thermogravimetric analysis (TGA)
• Polarimetry

Correct Answer: Fiber-optic UV/visible imaging (UV imaging)

Q7. Microdissolution or small-volume dissolution methods are advantageous because they:

• Always provide faster dissolution regardless of formulation
• Reduce media consumption, increase discriminating power for small samples or early development, and can mimic local GI conditions
• Replace the need for biorelevant media entirely
• Are only applicable to parenteral solutions

Correct Answer: Reduce media consumption, increase discriminating power for small samples or early development, and can mimic local GI conditions

Q8. Which biorelevant media are commonly used with alternative dissolution methods to simulate fed and fasted intestinal environments?

• Neutral buffered saline and pure ethanol only
• FaSSIF and FeSSIF (fasted and fed state simulated intestinal fluids)
• Distilled water adjusted to pH 7.0 only
• Oleic acid without bile salts

Correct Answer: FaSSIF and FeSSIF (fasted and fed state simulated intestinal fluids)

Q9. What is the practical meaning of maintaining “sink conditions” in dissolution testing?

• Drug concentration is allowed to reach and exceed saturation to study supersaturation effects
• The dissolution medium volume and composition keep dissolved drug concentration well below its saturation solubility to avoid limiting the dissolution rate
• Agitation is turned off during the test
• Only hydrophobic drugs are tested under these conditions

Correct Answer: The dissolution medium volume and composition keep dissolved drug concentration well below its saturation solubility to avoid limiting the dissolution rate

Q10. Microfluidic dissolution systems offer which of the following advantages?

• High sample consumption and limited control of hydrodynamics
• Precise control of flow and shear, low sample and media use, and potential for high-throughput, real-time monitoring
• They are always less predictive than conventional methods
• They cannot be coupled to analytical detectors

Correct Answer: Precise control of flow and shear, low sample and media use, and potential for high-throughput, real-time monitoring

Q11. Which statement correctly contrasts “sample-and-separate” dissolution with in situ analytical methods?

• Sample-and-separate measures drug release without physically removing aliquots
• Sample-and-separate requires periodic withdrawal and filtration or centrifugation of aliquots, whereas in situ methods measure concentration without removing medium
• In situ methods are always less accurate than sample-and-separate
• Sample-and-separate cannot be used with HPLC analysis

Correct Answer: Sample-and-separate requires periodic withdrawal and filtration or centrifugation of aliquots, whereas in situ methods measure concentration without removing medium

Q12. The term “discriminatory power” of a dissolution method refers to its ability to:

• Produce identical profiles for different formulations
• Detect meaningful differences between formulations or manufacturing variables that could affect in vivo performance
• Eliminate the need for dissolution specification setting
• Always predict bioavailability exactly

Correct Answer: Detect meaningful differences between formulations or manufacturing variables that could affect in vivo performance

Q13. Lipolysis models used as alternative dissolution tests are specifically designed to:

• Assess the dissolution of immediate-release tablets in acidic media only
• Study digestion and solubilization of lipid-based formulations by incorporating pancreatic enzymes and bile components
• Measure tablet disintegration time in water
• Replace permeability studies across epithelial membranes

Correct Answer: Study digestion and solubilization of lipid-based formulations by incorporating pancreatic enzymes and bile components

Q14. Why are surfactants sometimes added to dissolution media in alternative methods?

• To slow dissolution deliberately for all formulations
• To increase apparent solubility of poorly soluble drugs and help maintain sink conditions
• Because they neutralize drug chemical stability issues
• To make the medium opaque for imaging techniques

Correct Answer: To increase apparent solubility of poorly soluble drugs and help maintain sink conditions

Q15. One limitation of dialysis-based dissolution methods is:

• They provide instantaneous equilibrium between donor and receiver compartments
• Membrane-controlled diffusion can become rate-limiting and mask the true particle dissolution kinetics
• They cannot be used for nanoparticle formulations
• They eliminate the need to control temperature

Correct Answer: Membrane-controlled diffusion can become rate-limiting and mask the true particle dissolution kinetics

Q16. USP Apparatus 7 (reciprocating cylinder) is considered an alternative method because it:

• Is identical to USP Apparatus 2 in hydrodynamics
• Provides variable reciprocation rates and stroke lengths to better simulate gastrointestinal mechanical stresses
• Only works for transdermal patches
• Does not allow sampling during the test

Correct Answer: Provides variable reciprocation rates and stroke lengths to better simulate gastrointestinal mechanical stresses

Q17. What level of in vitro–in vivo correlation (IVIVC) represents a point-to-point relationship between in vitro dissolution and in vivo input rate?

• Level C IVIVC
• Level A IVIVC
• Level B IVIVC
• No correlation level is defined for dissolution

Correct Answer: Level A IVIVC

Q18. Which analytical approach is most suitable for high-specificity quantitation of drug in complex dissolution media with overlapping excipient UV absorbance?

• Direct UV absorbance at a single wavelength without separation
• HPLC with appropriate sample preparation and detection
• Gravimetric analysis of the dissolution medium
• Simple turbidity measurement

Correct Answer: HPLC with appropriate sample preparation and detection

Q19. Which imaging technique is best suited for non-destructive chemical mapping of drug distribution within a solid dosage form?

• Optical light microscopy without spectral capability
• Raman mapping/spectroscopic imaging
• Standard dissolution UV spectrophotometry without spatial resolution
• Thermal conductivity imaging

Correct Answer: Raman mapping/spectroscopic imaging

Q20. From a regulatory perspective, introducing an alternative dissolution method in place of a compendial test requires:

• No documentation if the new method is faster
• Scientific justification, validation demonstrating discriminatory power and reproducibility, and sometimes bridging studies to show equivalence or relevance to in vivo performance
• Only a notification to the analytical lab without validation
• Proof that the alternative method uses more expensive equipment

Correct Answer: Scientific justification, validation demonstrating discriminatory power and reproducibility, and sometimes bridging studies to show equivalence or relevance to in vivo performance

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