Formulation of pharmaceutical aerosols MCQs With Answer is a focused review resource for B. Pharm students covering aerosol science, device engineering, and formulation strategies. This set emphasizes metered-dose inhalers (MDIs), dry powder inhalers (DPIs), nebulizers, propellants (CFCs, HFAs), particle size distribution, aerodynamic diameter, aerosolization mechanisms, deposition (impaction, sedimentation, diffusion), excipients, preservatives, and stability challenges. Questions explore suspension versus solution formulations, valve and actuator design, respiratory performance metrics like emitted dose and fine particle fraction, and quality control tests such as cascade impactor analysis. Practical aspects include compatibility, processing (micronization, milling), humidity effects, and environmental considerations.
Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which parameter best defines the likelihood of a particle depositing in the lower respiratory tract?
- Geometric diameter
- Shape factor
- Aerodynamic diameter
Correct Answer: Aerodynamic diameter
Q2. Which propellant replaced CFCs in pressurized MDIs due to environmental regulations?
- Chloroform
- Hydrofluoroalkane (HFA)
- Propane
- Butane
Correct Answer: Hydrofluoroalkane (HFA)
Q3. Fine Particle Fraction (FPF) is defined as the percentage of emitted aerosol mass below which aerodynamic diameter?
- 10 µm
- 5 µm
- 1 µm
- 20 µm
Correct Answer: 5 µm
Q4. Which device typically requires the patient to generate sufficient inspiratory flow to disperse the formulation?
- Jet nebulizer
- Metered-dose inhaler with spacer
- Dry powder inhaler (DPI)
- Ultrasonic nebulizer
Correct Answer: Dry powder inhaler (DPI)
Q5. Which formulation type in MDIs is more prone to sedimentation and dose variability?
- Solution formulation
- Suspension formulation
- Gaseous formulation
- Aqueous aerosol from nebulizer
Correct Answer: Suspension formulation
Q6. Which test is commonly used to measure aerodynamic particle size distribution in regulatory testing?
- Viscometry
- Cascade impactor analysis
- DSC (Differential Scanning Calorimetry)
- UV-Vis spectrophotometry
Correct Answer: Cascade impactor analysis
Q7. What is the primary deposition mechanism for particles around 10 µm in the oropharynx?
- Brownian diffusion
- Gravitational sedimentation
- Inertial impaction
- Electrostatic attraction
Correct Answer: Inertial impaction
Q8. Which excipient in aerosol suspensions helps reduce particle aggregation and improve dispersion?
- Suspending agents like sorbitan esters
- Strong acids
- Heavy metals
- Organic dyes
Correct Answer: Suspending agents like sorbitan esters
Q9. What is the role of a metering valve in an MDI?
- Change the color of the aerosol
- Meter a reproducible dose per actuation
- Increase particle density
- Sterilize the formulation
Correct Answer: Meter a reproducible dose per actuation
Q10. Which property of DPI powders increases the risk of poor dispersibility under humid conditions?
- Hydrophobicity
- Low bulk density
- Hygroscopicity
- Low melting point
Correct Answer: Hygroscopicity
Q11. In aerosol formulation, what is the main reason for micronization of drug particles?
- Enhance taste
- Reduce chemical stability
- Achieve respirable particle size for pulmonary deposition
- Make particles visible
Correct Answer: Achieve respirable particle size for pulmonary deposition
Q12. Which nebulizer type is most suitable for heat-sensitive biologic drugs?
- Ultrasonic nebulizer
- Jet nebulizer
- Vibrating mesh nebulizer
- Pressurized MDI
Correct Answer: Vibrating mesh nebulizer
Q13. Which parameter differentiates emitted dose from delivered dose in inhaler performance?
- Chemical potency
- Loss in actuator or spacer and oropharyngeal deposition
- Color change during actuation
- Ambient light intensity
Correct Answer: Loss in actuator or spacer and oropharyngeal deposition
Q14. Which preservative commonly used in aqueous inhalation solutions has raised concerns about bronchoconstriction in sensitive patients?
- Sodium chloride
- Benzalkonium chloride
- Sorbitol
- Glycerin
Correct Answer: Benzalkonium chloride
Q15. What effect does increasing actuator orifice size generally have on plume and particle size?
- Smaller plume, smaller particles
- No effect on plume or particles
- Larger plume, larger droplet size
- Transforms aerosol into gas
Correct Answer: Larger plume, larger droplet size
Q16. Which test evaluates the uniformity of delivered doses from MDIs over repeated actuations?
- Thermogravimetric analysis
- Dose uniformity test
- DSC melting point test
- Gel electrophoresis
Correct Answer: Dose uniformity test
Q17. What is a common challenge when formulating aqueous MDIs compared to HFA formulations?
- Greater environmental harm
- Propellant incompatibility
- Microbial contamination and need for preservatives
- Excessive vapor pressure
Correct Answer: Microbial contamination and need for preservatives
Q18. Which factor most strongly influences aerosol deposition by diffusion in the alveolar region?
- Particle aerodynamic diameter >10 µm
- Particle density only
- Very small particle size (<0.5 µm)
- Color of formulation
Correct Answer: Very small particle size (<0.5 µm)
Q19. Why are spacer devices recommended with MDIs for some patients?
- To reduce medication stability
- To increase oropharyngeal deposition
- To improve coordination between actuation and inhalation and reduce oropharyngeal deposition
- To heat the aerosol
Correct Answer: To improve coordination between actuation and inhalation and reduce oropharyngeal deposition
Q20. Which material interaction is a concern for aerosol formulations stored in plastic containers?
- Surface crystallization enhancement
- Sorption of drug or propellant into plastic and extractables/leachables
- Improved chemical stability always
- Increased emitted dose exclusively
Correct Answer: Sorption of drug or propellant into plastic and extractables/leachables
Q21. What is the effect of using ethanol as a co-solvent in HFA formulations?
- Prevents aerosolization entirely
- Acts as a cosolvent to improve drug solubility and alter plume characteristics
- Causes immediate precipitation of drug
- Neutralizes propellant
Correct Answer: Acts as a cosolvent to improve drug solubility and alter plume characteristics
Q22. Which measurement quantifies particle mass reaching the lower airways in aerosol testing?
- Fine Particle Dose (FPD)
- Colorimetric index
- Bulk powder density
- Viscosity
Correct Answer: Fine Particle Dose (FPD)
Q23. In suspension MDIs, which process helps maintain content uniformity during storage?
- Avoiding micronization
- Using appropriate suspending agents and flocculating agents to control sedimentation
- Removing the valve
- Increasing particle size to millimeter range
Correct Answer: Using appropriate suspending agents and flocculating agents to control sedimentation
Q24. Which property of a spray characterizes how quickly aerosol droplets decelerate after leaving the actuator?
- Plume geometry and velocity profile
- Electrical conductivity
- pH
- Melting point
Correct Answer: Plume geometry and velocity profile
Q25. For inhaled proteins and peptides, which formulation concern is most critical?
- Taste masking in the oropharynx
- Chemical and physical stability (aggregation, denaturation) during aerosolization
- High melting point
- Color stability
Correct Answer: Chemical and physical stability (aggregation, denaturation) during aerosolization
Q26. Which device parameter is adjusted to control the metered volume in a pMDI valve system?
- Actuator color
- Metering chamber volume of the valve
- Label text size
- Ambient humidity
Correct Answer: Metering chamber volume of the valve
Q27. What is the main advantage of breath-actuated inhalers for patients?
- They require complex priming by the user
- They eliminate the need for coordination between actuation and inhalation
- They always deliver larger particles
- They are more likely to cause contamination
Correct Answer: They eliminate the need for coordination between actuation and inhalation
Q28. Which factor most reduces aerosol output from a jet nebulizer during use?
- Low residual volume in the nebulizer cup
- Clogged air-jet or compressed air supply issues
- Using distilled water only
- Increasing the drug concentration
Correct Answer: Clogged air-jet or compressed air supply issues
Q29. During DPI formulation, why are carrier particles like lactose used?
- To chemically react with the drug
- To improve powder flow, dispersion and aid dose metering
- To dissolve the drug during inhalation
- To increase hygroscopicity
Correct Answer: To improve powder flow, dispersion and aid dose metering
Q30. Which environmental concern is associated with some aerosol propellants and has driven formulation changes?
- Increase in ambient temperature only
- Ozone depletion and global warming potential of certain propellants
- Increase in soil acidity
- Excessive noise pollution
Correct Answer: Ozone depletion and global warming potential of certain propellants
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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