Preformulation studies are the foundation for developing robust solid dosage forms and essential for every B. Pharm student. This introduction covers the application of preformulation including evaluation of physicochemical properties, drug-excipient compatibility, solubility, particle size, polymorphism, stability, and dissolution behavior. Understanding analytical tools like DSC, FTIR, XRD and thermogravimetric analysis, as well as addressing hygroscopicity and moisture sensitivity, guides rational excipient selection and formulation design. Emphasis on data-driven decisions reduces development risk and ensures product quality. These concepts will be reinforced through practical, focused questions that test conceptual understanding and application. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which primary goal of preformulation is most important for designing a stable solid oral dosage form?
- Identifying the marketing strategy
- Evaluating physicochemical properties of the drug
- Optimizing manufacturing cost
- Selecting packaging design
Correct Answer: Evaluating physicochemical properties of the drug
Q2. Which parameter best predicts solubility and membrane permeability for a drug candidate?
- Melting point
- Partition coefficient (Log P)
- Color of drug powder
- Bulk density
Correct Answer: Partition coefficient (Log P)
Q3. Which technique is most appropriate to detect molecular interactions between drug and excipient during compatibility studies?
- UV-Visible color matching
- Fourier-transform infrared spectroscopy (FTIR)
- Optical microscopy for color
- Tap density measurement
Correct Answer: Fourier-transform infrared spectroscopy (FTIR)
Q4. Polymorphism in a drug substance primarily affects which of the following properties?
- Tablet imprint clarity
- Solubility and dissolution rate
- Bottle cap fit
- Color only
Correct Answer: Solubility and dissolution rate
Q5. Which preformulation test quantifies moisture uptake by a solid drug at specified relative humidities?
- Accelerated stability chamber testing
- Moisture sorption isotherm
- Intrinsic dissolution rate
- Particle size distribution
Correct Answer: Moisture sorption isotherm
Q6. Differential scanning calorimetry (DSC) is mainly used in preformulation to:
- Measure microbial contamination
- Assess thermal transitions like melting and crystallinity
- Determine solubility in solvents
- Measure tablet hardness
Correct Answer: Assess thermal transitions like melting and crystallinity
Q7. Which property is most directly assessed by measuring bulk and tapped density?
- Chemical stability
- Flowability and packing behavior
- Pharmacokinetics
- pH stability
Correct Answer: Flowability and packing behavior
Q8. A drug with very low water solubility and high lipophilicity would most likely benefit from which preformulation strategy?
- Salt formation to improve solubility
- Reducing particle size and using solubilizers
- Adding hydrophobic lubricants
- Increasing tablet compression force only
Correct Answer: Reducing particle size and using solubilizers
Q9. Intrinsic dissolution rate (IDR) is measured under what condition?
- Using powdered drug dispersed in media
- Using a constant surface area of compressed drug
- Using varied pH for each measurement
- After blending with excipients
Correct Answer: Using a constant surface area of compressed drug
Q10. Which parameter indicates poor powder flow and risk of segregation during processing?
- Low angle of repose
- High Carr’s index (compressibility)
- High drug purity
- Low moisture content
Correct Answer: High Carr’s index (compressibility)
Q11. Why is pKa important in preformulation for solid oral drugs?
- It determines the drug’s color in tablets
- It influences pH-dependent solubility and ionization state
- It defines the melting point
- It measures particle density
Correct Answer: It influences pH-dependent solubility and ionization state
Q12. X-ray powder diffraction (XRD) is primarily used to:
- Measure moisture content
- Determine crystalline versus amorphous character
- Assess surface charge
- Test tablet disintegration
Correct Answer: Determine crystalline versus amorphous character
Q13. Which excipient property is crucial to evaluate during preformulation for tableting?
- Melting point above 300°C only
- Compressibility and compactibility
- Ability to change drug’s chemical structure
- Color matching with brand logo
Correct Answer: Compressibility and compactibility
Q14. Forced degradation studies in preformulation are intended to:
- Accelerate dissolution rate
- Identify degradation pathways and develop stability-indicating methods
- Measure powder flow
- Improve tablet taste
Correct Answer: Identify degradation pathways and develop stability-indicating methods
Q15. Which factor most influences tablet hardness and friability during formulation?
- Excipient color
- Compression force and binder selection
- Ambient light exposure
- Packaging label
Correct Answer: Compression force and binder selection
Q16. Hygroscopicity of a drug affects which of the following formulation decisions?
- Choice of tablet imprint font
- Packaging requirements and desiccant use
- Marketing claims
- Expiration date format
Correct Answer: Packaging requirements and desiccant use
Q17. Which is the best method to determine if a drug exists as different polymorphs?
- pH solubility profile only
- XRD combined with DSC and microscopy
- Tap density measurement
- Colorimetric titration
Correct Answer: XRD combined with DSC and microscopy
Q18. Why is particle size distribution critical in solid dosage form development?
- It only affects the tablet color
- It influences dissolution, content uniformity, and flow
- It dictates marketing price
- It prevents microbial growth
Correct Answer: It influences dissolution, content uniformity, and flow
Q19. Which preformulation outcome supports selection of immediate-release tablets over sustained-release?
- High aqueous solubility and rapid dissolution
- High melting point and low solubility
- Strong hygroscopicity
- Poor compressibility
Correct Answer: High aqueous solubility and rapid dissolution
Q20. Compatibility screening of drug with excipients at elevated temperature is typically performed to:
- Evaluate long-term clinical efficacy
- Predict potential incompatibilities and degradation under stress
- Improve taste masking
- Determine dissolution in organic solvents
Correct Answer: Predict potential incompatibilities and degradation under stress
Q21. Which property is assessed by measuring zeta potential for solid particles in suspension?
- Thermal stability
- Surface charge and colloidal stability
- Crystal habit
- Moisture sorption
Correct Answer: Surface charge and colloidal stability
Q22. Salt formation during preformulation is primarily used to:
- Reduce molecular weight
- Modify solubility and dissolution rate
- Change color of drug
- Increase hygroscopicity intentionally
Correct Answer: Modify solubility and dissolution rate
Q23. Which analytical method is most suitable as a stability-indicating assay in preformulation?
- Non-specific colorimetric test
- Validated HPLC capable of separating degradation products
- Simple gravimetric analysis
- Turbidity measurement only
Correct Answer: Validated HPLC capable of separating degradation products
Q24. What does a high hygroscopicity classify a drug as, in terms of formulation handling?
- Non-reactive and stable in air
- Moisture sensitive requiring controlled environment
- Easy to compress without binders
- Insoluble in water
Correct Answer: Moisture sensitive requiring controlled environment
Q25. Which preformulation parameter directly affects content uniformity in low-dose tablets?
- Particle size and blend uniformity
- Tablet coating color
- Dissolution medium pH
- Compression speed only
Correct Answer: Particle size and blend uniformity
Q26. Which test would you use to evaluate the compactibility of a powder for direct compression?
- Moisture sorption isotherm only
- Compression profile and tablet strength testing
- FTIR spectroscopy
- Viscosity measurement
Correct Answer: Compression profile and tablet strength testing
Q27. In preformulation, a drug showing exothermic peaks in DSC on aging suggests:
- Improved solubility over time
- Possible degradation or recrystallization events
- No change in solid state
- Higher bulk density
Correct Answer: Possible degradation or recrystallization events
Q28. Which excipient interaction would most likely reduce drug dissolution?
- Formation of insoluble complexes with excipient
- Use of soluble disintegrant
- Using hydrophilic wetting agents
- Reducing particle size
Correct Answer: Formation of insoluble complexes with excipient
Q29. Why is accelerated stability testing (e.g., 40°C/75% RH) performed during preformulation?
- To evaluate immediate release in vivo
- To predict long-term stability and identify degradation under stress
- To measure tablet hardness only
- To determine taste masking efficiency
Correct Answer: To predict long-term stability and identify degradation under stress
Q30. Which combination of techniques best supports a thorough preformulation solid-state characterization?
- UV spectrophotometry and tap density
- DSC, XRD, FTIR and particle size analysis
- Packaging design and label testing
- Color matching and odor sensory tests
Correct Answer: DSC, XRD, FTIR and particle size analysis
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
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