Protein formulation strategies MCQs With Answer

Protein formulation strategies MCQs With Answer is a focused question set designed for M.Pharm students specializing in Proteins and Protein Formulations. This collection reinforces core concepts in protein stabilization, excipient selection, processing techniques (lyophilization, freeze–thaw), chemical degradation pathways (oxidation, deamidation), and delivery considerations (cold chain, container interactions, controlled release). Each MCQ emphasizes mechanistic understanding and practical formulation choices encountered during development of therapeutic proteins and biologics. Use these questions to test your ability to apply theoretical principles to real-world formulation challenges, prepare for exams, and identify areas needing deeper study in advanced protein formulation strategies.

Q1. What is the primary objective of protein formulation development?

• To maximize yield during protein expression
• To modify the amino acid sequence for higher activity
• To preserve protein structural integrity and biological activity during storage and administration
• To reduce manufacturing costs by removing stabilizers

Correct Answer: To preserve protein structural integrity and biological activity during storage and administration

Q2. Which excipient stabilizes proteins primarily via preferential exclusion and water replacement during drying?

• Polysorbate 80
• Trehalose
• Sodium chloride
• Citrate buffer

Correct Answer: Trehalose

Q3. What is the main benefit of lyophilization for protein therapeutics?

• Improves solubility by increasing ionic strength
• Removes water to reduce hydrolytic and some degradative reactions, improving long-term stability
• Increases protein immunogenicity to enhance response
• Replaces the need for cold-chain storage entirely

Correct Answer: Removes water to reduce hydrolytic and some degradative reactions, improving long-term stability

Q4. How do nonionic surfactants (e.g., polysorbates) primarily protect proteins in formulations?

• By covalently binding to hydrophobic patches on proteins
• By occupying air–liquid and solid–liquid interfaces, reducing surface-induced denaturation and aggregation
• By acting as chelators to prevent metal-catalyzed oxidation
• By lowering solution pH to suppress deamidation

Correct Answer: By occupying air–liquid and solid–liquid interfaces, reducing surface-induced denaturation and aggregation

Q5. What is a primary effect of PEGylation on therapeutic proteins?

• Increases enzymatic activity by exposing active sites
• Enhances renal clearance to reduce exposure
• Increases plasma half-life and can reduce immunogenicity by steric shielding
• Always prevents all aggregation mechanisms

Correct Answer: Increases plasma half-life and can reduce immunogenicity by steric shielding

Q6. Which buffering system is commonly preferred for monoclonal antibody formulations near neutral pH due to good buffering capacity and low reactivity?

• Citrate buffer
• Acetate buffer
• Histidine buffer
• Glycine buffer at pH 3

Correct Answer: Histidine buffer

Q7. What is a common mechanistic cause of protein aggregation during freeze–thaw cycles?

• Enhanced enzymatic refolding in the frozen state
• Concentration of protein and excipients at ice–liquid interfaces leading to unfolding and aggregation
• Permanent chemical crosslinking by ice crystals
• Complete protection by buffers during freezing

Correct Answer: Concentration of protein and excipients at ice–liquid interfaces leading to unfolding and aggregation

Q8. Deamidation most commonly affects which amino acid residue in proteins?

• Methionine
• Asparagine
• Tyrosine
• Proline

Correct Answer: Asparagine

Q9. Which amino acid residue is most susceptible to oxidation in proteins and often monitored during formulation development?

• Alanine
• Methionine
• Valine
• Leucine

Correct Answer: Methionine

Q10. Which container–closure interaction is a notable risk for protein formulations?

• Proteins increasing glass transition temperature of the vial
• Leachables and extractables from rubber stoppers or plastics that induce aggregation or degradation
• Rising buffer pH due to stainless steel vials
• Intrinsic digestion of proteins by glass surfaces

Correct Answer: Leachables and extractables from rubber stoppers or plastics that induce aggregation or degradation

Q11. What is a formulation challenge associated with very high protein concentrations used for subcutaneous injections?

• Decreased stability due to immediate precipitation only
• Reduced viscosity and easier syringeability
• Increased viscosity, risk of self-association and aggregation, and syringeability issues
• Elimination of need for stabilizing excipients

Correct Answer: Increased viscosity, risk of self-association and aggregation, and syringeability issues

Q12. Which excipient is commonly used to adjust isotonicity of a parenteral protein formulation without significantly affecting protein stability?

• Polyethylene glycol 4000
• Sodium chloride
• EDTA at high concentration
• Sodium azide

Correct Answer: Sodium chloride

Q13. Which analytical technique is most appropriate for quantifying soluble protein aggregates in a formulation?

• Size-exclusion chromatography (SEC)
• UV–Vis absorbance without separation
• Reverse-phase HPLC without denaturation
• Infrared spectroscopy for secondary structure only

Correct Answer: Size-exclusion chromatography (SEC)

Q14. Why are metal chelators (e.g., EDTA) sometimes included in protein formulations?

• To catalyze oxidation for rapid testing
• To stabilize tertiary structure by binding to protein active sites
• To bind trace metal ions and reduce metal-catalyzed oxidation and degradation
• To act as primary buffering species at physiological pH

Correct Answer: To bind trace metal ions and reduce metal-catalyzed oxidation and degradation

Q15. Polysorbate degradation in formulations commonly leads to which problematic outcome?

• Complete removal of all surfactant from solution with no consequences
• Generation of free fatty acid and peroxides that can increase subvisible particles and promote protein aggregation
• Instant pH neutralization
• Formation of covalent PEG–protein adducts improving stability

Correct Answer: Generation of free fatty acid and peroxides that can increase subvisible particles and promote protein aggregation

Q16. What is a major challenge when formulating proteins into PLGA microspheres for sustained release?

• PLGA microspheres always increase protein thermal stability
• Creation of an acidic microenvironment during polymer degradation that can denature the encapsulated protein
• Complete prevention of proteolytic degradation in vivo
• Instant release without controlled kinetics

Correct Answer: Creation of an acidic microenvironment during polymer degradation that can denature the encapsulated protein

Q17. How does solution osmolality affect parenteral protein administration?

• Hypertonic solutions generally reduce injection site irritation
• Hypotonic solutions improve long-term protein stability
• Hypertonic or hypotonic solutions can cause local pain, tissue damage, or hemolysis; isotonicity is preferred
• Osmolality has no impact on patient tolerance

Correct Answer: Hypertonic or hypotonic solutions can cause local pain, tissue damage, or hemolysis; isotonicity is preferred

Q18. What is the commonly recommended refrigerated storage temperature range for many monoclonal antibody formulations?

• -80 to -60 °C
• 2 to 8 °C
• 25 to 30 °C
• Above 40 °C for accelerated stability

Correct Answer: 2 to 8 °C

Q19. Which statement best describes the usual pathway from native protein to irreversible aggregated species?

• Irreversible covalent aggregates form first, then reversible oligomers appear
• Proteins directly fragment into small peptides without intermediate steps
• Native → partially unfolded noncovalent oligomers (reversible) → covalent cross-linked aggregates (irreversible)
• All aggregation is always reversible with correct buffer

Correct Answer: Native → partially unfolded noncovalent oligomers (reversible) → covalent cross-linked aggregates (irreversible)

Q20. When selecting a buffer for a protein formulation, which property of the buffer is most important to ensure effective pH control?

• Buffer concentration should always be below 1 mM
• Buffer pKa should be within about one pH unit of the target formulation pH
• Buffer must have aromatic groups to stabilize proteins
• Buffer must contain divalent metal ions for stability

Correct Answer: Buffer pKa should be within about one pH unit of the target formulation pH

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