Introduction to preformulation MCQs With Answer

Introduction to preformulation MCQs With Answer

This focused introduction to preformulation MCQs with answers guides B.Pharm students through essential preformulation concepts such as drug solubility, pKa, partition coefficient, polymorphism, stability, particle size, excipient compatibility and analytical techniques (DSC, XRD, FTIR). Emphasis is placed on physicochemical characterization, dissolution behavior, degradation pathways and formulation-relevant parameters like hygroscopicity, flow properties and salt selection. These MCQs reinforce critical thinking for formulation development, quality control and regulatory considerations, helping students prepare for exams and practical formulation tasks. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the primary objective of preformulation studies?

• To perform clinical trials on a new drug
• To characterize physicochemical properties of the drug substance
• To market the finished pharmaceutical product
• To design patient dosing regimens

Correct Answer: To characterize physicochemical properties of the drug substance

Q2. Which two properties are most critical in assessing oral drug absorption during preformulation?

• Color and odor
• Solubility and permeability
• Melting point and refractive index
• Zeta potential and microbial load

Correct Answer: Solubility and permeability

Q3. What does pKa represent for a drug molecule?

• The molecular weight of the drug
• The pH at which the drug is 50% ionized
• The temperature at which the drug degrades
• The partition coefficient between two phases

Correct Answer: The pH at which the drug is 50% ionized

Q4. Which equation relates pH, pKa and the ratio of ionized to unionized drug?

• Arrhenius equation
• Henderson-Hasselbalch equation
• Van’t Hoff equation
• Michaelis-Menten equation

Correct Answer: Henderson-Hasselbalch equation

Q5. A drug with high log P is generally:

• Highly hydrophilic
• Highly lipophilic
• Extremely unstable
• Non-ionizable at physiological pH

Correct Answer: Highly lipophilic

Q6. Which technique is most appropriate to detect crystalline versus amorphous solid forms?

• UV-visible spectroscopy
• X-ray powder diffraction (XRD)
• High-performance liquid chromatography (HPLC)
• Microbiological assay

Correct Answer: X-ray powder diffraction (XRD)

Q7. Differential scanning calorimetry (DSC) is used in preformulation to determine:

• pH of the drug solution
• Thermal transitions like melting point and polymorphic transitions
• Particle size distribution
• Surface charge

Correct Answer: Thermal transitions like melting point and polymorphic transitions

Q8. Which property most directly affects powder flow and tablet compressibility?

• UV absorbance
• Particle size and shape
• Glass transition temperature only
• Partition coefficient

Correct Answer: Particle size and shape

Q9. What does a high Hausner ratio (>1.25) indicate about a powder?

• Excellent flowability
• Poor flowability and high cohesiveness
• Low moisture sorption
• High solubility in water

Correct Answer: Poor flowability and high cohesiveness

Q10. Which parameter assesses the tendency of a solid to absorb moisture from the environment?

• Hygroscopicity
• pKa
• Partition coefficient
• Viscosity

Correct Answer: Hygroscopicity

Q11. Why is salt selection important in preformulation?

• To reduce manufacturing costs only
• To improve solubility, stability and bioavailability of ionizable drugs
• To change the color of dosage forms
• To increase the molecular weight

Correct Answer: To improve solubility, stability and bioavailability of ionizable drugs

Q12. Which analytical method is commonly used to identify drug-excipient chemical incompatibilities?

• Nuclear magnetic resonance for mass determination
• FTIR spectroscopy to detect functional group interactions
• Optical microscopy for microbial contamination
• pH meter for dissolution rate

Correct Answer: FTIR spectroscopy to detect functional group interactions

Q13. Photostability studies in preformulation evaluate:

• Stability of drug under light exposure and formulation protection needs
• Only thermal degradation pathways
• Lipid oxidation in emulsions
• Only microbial growth under light

Correct Answer: Stability of drug under light exposure and formulation protection needs

Q14. Which property influences the rate of dissolution of a solid drug?

• Particle size and surface area
• Color of the formulation
• Packaging material thickness
• Company logo design

Correct Answer: Particle size and surface area

Q15. What does XRD detect that DSC might not clearly distinguish?

• Thermal decomposition products
• Crystalline lattice and specific polymorphic forms
• pH-dependent ionization
• Surface area

Correct Answer: Crystalline lattice and specific polymorphic forms

Q16. A drug that degrades rapidly at elevated temperature: which preformulation test is critical?

• Particle size analysis only
• Accelerated stability studies and thermal analysis (TGA/DSC)
• Only partition coefficient measurement
• Colorimetric assay for impurities

Correct Answer: Accelerated stability studies and thermal analysis (TGA/DSC)

Q17. Which factor most directly affects wetting and dissolution of poorly wettable powders?

• Surface tension and use of surfactants
• Bulk density only
• Melting point only
• Optical rotation

Correct Answer: Surface tension and use of surfactants

Q18. Which measurement provides information about surface charge and colloidal stability?

• Zeta potential
• Melting point
• pKa
• Bulk density

Correct Answer: Zeta potential

Q19. What is the significance of polymorphism in drug substances?

• Only affects color, not performance
• Different polymorphs can show different solubility, stability and bioavailability
• Polymorphism refers to microbial contamination
• It indicates the presence of impurities only

Correct Answer: Different polymorphs can show different solubility, stability and bioavailability

Q20. In preformulation, residual solvent analysis is important because:

• Residual solvents can affect toxicity and stability of the final product
• They always improve drug solubility
• They determine particle size
• They are irrelevant to regulatory submissions

Correct Answer: Residual solvents can affect toxicity and stability of the final product

Q21. Which preformulation parameter helps predict physical stability against caking?

• Bulk and tapped density with compressibility index
• Log P only
• pKa only
• UV spectrum

Correct Answer: Bulk and tapped density with compressibility index

Q22. A weak acid drug (pKa 4.5) will be mostly ionized at which pH?

• pH 2.0
• pH 4.5
• pH 7.4
• pH 1.0

Correct Answer: pH 7.4

Q23. Which property is essential to study for injectable formulations in preformulation?

• Particle size and sub-visible particulate content
• Tablet hardness
• Capsule color uniformity
• Taste masking

Correct Answer: Particle size and sub-visible particulate content

Q24. Which technique is most suitable to monitor moisture-induced changes in a drug sample?

• Thermogravimetric analysis (TGA)
• ELISA
• HPLC with fluorescence only
• Optical rotation

Correct Answer: Thermogravimetric analysis (TGA)

Q25. Buffer capacity in preformulation matters because:

• It influences the pH stability and degree of ionization of the drug
• Buffers always make drugs insoluble
• It is unrelated to dissolution
• Buffers increase particle size

Correct Answer: It influences the pH stability and degree of ionization of the drug

Q26. What is a stability-indicating method?

• An assay that quantifies the drug without separating degradation products
• An analytical method that accurately measures the drug and separates degradation products
• A method to check tablet color only
• A technique to determine bulk density

Correct Answer: An analytical method that accurately measures the drug and separates degradation products

Q27. Which degradation pathway is commonly accelerated by heat and moisture?

• Hydrolysis
• Photolysis only
• Enzymatic degradation only
• Oxidation unaffected by moisture

Correct Answer: Hydrolysis

Q28. When designing dissolution media in preformulation, why simulate physiological conditions?

• To estimate in vivo dissolution and absorption behavior
• To increase manufacturing speed
• To avoid analytical method development
• To reduce drug potency intentionally

Correct Answer: To estimate in vivo dissolution and absorption behavior

Q29. Which preformulation test provides insight into possible chemical incompatibilities over time?

• Forced degradation studies at stress conditions
• Only organoleptic testing
• Color matching tests
• Capsule filling speed test

Correct Answer: Forced degradation studies at stress conditions

Q30. Why is particle engineering (e.g., micronization, spray drying) performed during preformulation?

• To change the API’s molecular formula
• To optimize particle size, surface area and solid state for improved solubility, dissolution and stability
• To eliminate the need for excipients
• To increase the drug’s pKa

Correct Answer: To optimize particle size, surface area and solid state for improved solubility, dissolution and stability

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