Aerosols and inhalers are essential study areas for B. Pharm students, linking pharmaceutics, clinical therapy, and patient counselling. This introduction highlights aerosol therapy principles, device classifications (MDIs, DPIs, nebulizers), formulation science (propellants, co-solvents, carriers), particle engineering (MMAD, FPF, aerodynamic behavior), device performance tests (cascade impactor, dose uniformity, spray pattern), and practical aspects such as inhaler technique, spacer use, stability and regulatory issues. Focused, keyword-rich content prepares students for exams and pharmacy practice by exploring both theoretical concepts and formulation challenges in depth. Now let’s test your knowledge with 50 MCQs on this topic.
Q1. Which device generates an aerosol by converting liquid medication into droplets using compressed gas or ultrasonic energy?
- Nebulizer
- Dry Powder Inhaler
- Metered-Dose Inhaler
- Spacer
Correct Answer: Nebulizer
Q2. Which class of propellants replaced CFCs in modern MDIs due to ozone safety concerns?
- Hydrofluoroalkanes (HFAs)
- Chlorofluorocarbons (CFCs)
- Hydrocarbons (butane)
- Compressed air
Correct Answer: Hydrofluoroalkanes (HFAs)
Q3. What is the primary clinical benefit of using a spacer with an MDI?
- Reduce oropharyngeal deposition and improve lung delivery
- Increase propellant pressure
- Allow use without priming
- Convert the formulation to a dry powder
Correct Answer: Reduce oropharyngeal deposition and improve lung delivery
Q4. What does MMAD stand for in aerosol characterization?
- Mass Median Aerodynamic Diameter
- Mean Mechanical Aerosol Density
- Maximum Measured Aerosol Distribution
- Median Mass Aerosol Dose
Correct Answer: Mass Median Aerodynamic Diameter
Q5. Deposition by inertial impaction is most significant for particles of which size range?
- Greater than 5 µm
- Between 1 and 3 µm
- Smaller than 0.5 µm
- Exactly 5 µm only
Correct Answer: Greater than 5 µm
Q6. Fine particle fraction (FPF) typically refers to the percentage of emitted dose with particle size below what cutoff?
- 5 µm
- 10 µm
- 0.5 µm
- 20 µm
Correct Answer: 5 µm
Q7. Which carrier is most commonly used in carrier-based dry powder inhaler formulations?
- Lactose
- Starch
- Cellulose acetate
- Mannitol
Correct Answer: Lactose
Q8. Which analytical technique is considered the gold standard for measuring aerodynamic particle size distribution of inhaled products?
- Cascade impactor
- UV-visible spectrophotometry
- High-performance liquid chromatography
- Gas chromatography
Correct Answer: Cascade impactor
Q9. Which excipient is commonly used as a co-solvent in HFA MDI formulations to improve drug solubility?
- Ethanol
- Propylene glycol
- Polyethylene glycol 4000
- Glycerin
Correct Answer: Ethanol
Q10. Which type of MDI formulation typically requires shaking before use to ensure dose uniformity?
- Suspension MDI
- Solution MDI
- Dry powder cartridge
- Breath-actuated DPI
Correct Answer: Suspension MDI
Q11. A spacer primarily reduces which of the following risks associated with inhaled corticosteroids?
- Oral candidiasis
- Systemic hypertension
- Immediate bronchospasm
- Propellant toxicity
Correct Answer: Oral candidiasis
Q12. What is “priming” of an MDI?
- Actuating the device into the air before first use to ensure proper dose delivery
- Cleaning the actuator with water
- Attaching a spacer permanently
- Loading powder into a DPI capsule
Correct Answer: Actuating the device into the air before first use to ensure proper dose delivery
Q13. Which component of an MDI determines the metered amount of formulation released per actuation?
- Metering valve
- Actuator mouthpiece
- Canister cap
- Spacer chamber
Correct Answer: Metering valve
Q14. For effective use of a dry powder inhaler (DPI), the recommended inhalation technique is:
- A forceful, deep inhalation
- A slow, shallow inhalation
- Exhale into the device before inhaling deeply
- Activate the device during exhalation
Correct Answer: A forceful, deep inhalation
Q15. What is the primary function of lactose in carrier-based DPI formulations?
- Improve powder flow and reduce cohesive forces
- Act as a propellant
- Stabilize aqueous suspension
- Serve as an antimicrobial preservative
Correct Answer: Improve powder flow and reduce cohesive forces
Q16. HFA-134a is the common name for which chemical?
- 1,1,1,2-Tetrafluoroethane
- Chlorodifluoromethane
- 1,1,1-Trichloroethane
- n-Butane
Correct Answer: 1,1,1,2-Tetrafluoroethane
Q17. Which particle property most strongly influences regional lung deposition?
- Aerodynamic diameter
- Geometric shape only
- Chemical solubility only
- Color of the powder
Correct Answer: Aerodynamic diameter
Q18. Which industrial process is commonly used to reduce drug particle size for inhalation formulations?
- Jet milling (air jet micronization)
- Spray drying without atomization
- Simple crushing with mortar and pestle
- Lyophilization of suspensions
Correct Answer: Jet milling (air jet micronization)
Q19. What does FPF stand for in inhaler performance metrics?
- Fine Particle Fraction
- Full Powder Flow
- First Pass Fraction
- Functional Propellant Flow
Correct Answer: Fine Particle Fraction
Q20. Which test evaluates the spatial distribution of droplets within an inhaler plume at the actuator?
- Spray pattern test
- Leakage test
- pH determination
- Disintegration test
Correct Answer: Spray pattern test
Q21. For which patient group is a jet nebulizer with a face mask particularly recommended?
- Infants and very young children
- Patients able to use DPIs reliably
- Adults who can coordinate MDIs
- Patients requiring single deep inhalations
Correct Answer: Infants and very young children
Q22. Which inhaler type is breath-actuated to reduce coordination requirements?
- Autohaler (breath-actuated MDI)
- Rotahaler (manual DPI)
- Turbuhaler (manual DPI)
- Traditional press-and-breathe MDI without mechanism
Correct Answer: Autohaler (breath-actuated MDI)
Q23. Using a spacer with an inhaled corticosteroid primarily reduces which unwanted outcome?
- Local oropharyngeal side effects such as thrush
- Systemic blood glucose reduction
- Device manufacturing variability
- Particle hygroscopic growth
Correct Answer: Local oropharyngeal side effects such as thrush
Q24. Which device relies on patient inspiratory flow to disperse and deliver the powder dose?
- Dry Powder Inhaler (DPI)
- Metered-Dose Inhaler (MDI)
- Nebulizer
- Spacer without device
Correct Answer: Dry Powder Inhaler (DPI)
Q25. What is the “emitted dose” of an inhaler?
- The amount of drug leaving the device mouthpiece per actuation
- The mass of propellant in the canister
- The total formulation inside the canister
- The fraction retained in the actuator only
Correct Answer: The amount of drug leaving the device mouthpiece per actuation
Q26. Geometric standard deviation (GSD) in aerosol science describes which aspect?
- Width of the particle size distribution
- Chemical stability of the drug
- Volume of the spacer
- Rate of propellant evaporation
Correct Answer: Width of the particle size distribution
Q27. Which parameter is directly obtained from cascade impactor testing?
- Mass median aerodynamic diameter (MMAD)
- pH of formulation
- Viscosity of the propellant
- Device resistance rating
Correct Answer: Mass median aerodynamic diameter (MMAD)
Q28. A common user error that reduces lung delivery from an MDI is:
- Failing to shake a suspension MDI before actuation
- Using a spacer with the device
- Priming before first use
- Exhaling completely before inhalation
Correct Answer: Failing to shake a suspension MDI before actuation
Q29. Why is ethanol included in many HFA MDI formulations?
- Acts as a co-solvent to improve drug solubility and formulation stability
- Serves as the primary propellant
- Functions as an antimicrobial preservative only
- Makes the formulation hygroscopic
Correct Answer: Acts as a co-solvent to improve drug solubility and formulation stability
Q30. Which inhaler type is most sensitive to environmental humidity and usually requires moisture protection in packaging?
- Dry Powder Inhaler (DPI)
- Metered-Dose Inhaler (MDI)
- Jet Nebulizer
- Soft mist inhaler
Correct Answer: Dry Powder Inhaler (DPI)
Q31. Large oropharyngeal deposition is most commonly caused by which factor?
- Large particle size (e.g., >5 µm) and high aerosol velocity
- Excessive inspiratory flow only
- Use of lactose carrier in DPI
- Presence of ethanol in MDI
Correct Answer: Large particle size (e.g., >5 µm) and high aerosol velocity
Q32. Which formulation strategy improves deagglomeration of drug particles in a DPI?
- Use of coarse lactose carrier and optimized blending
- Elimination of carrier entirely in all cases
- Increasing propellant pressure
- Adding water to the powder
Correct Answer: Use of coarse lactose carrier and optimized blending
Q33. The actuator orifice size in an MDI primarily influences which outcome?
- Spray velocity and droplet size distribution
- The chemical potency of the drug
- Particle hygroscopicity
- The lactose carrier performance
Correct Answer: Spray velocity and droplet size distribution
Q34. Which international agreement led to the global phase-out of CFC propellants?
- Montreal Protocol
- Kyoto Protocol
- Helsinki Agreement
- Geneva Convention
Correct Answer: Montreal Protocol
Q35. Compared to MDIs, nebulizers are generally:
- Less dependent on patient coordination and suitable for very young or severely ill patients
- More portable and breath-activated
- Always deliver a smaller particle size than MDIs
- Drug only delivered as dry powder
Correct Answer: Less dependent on patient coordination and suitable for very young or severely ill patients
Q36. “Dose uniformity” testing for an inhaler ensures:
- Each actuation delivers a consistent amount of active drug
- The propellant evaporates uniformly
- The device mouthpiece remains clean
- The actuator color does not fade
Correct Answer: Each actuation delivers a consistent amount of active drug
Q37. Which manufacturing step is critical for producing carrier-based DPI formulations?
- Sieving and blending of drug with carrier (e.g., lactose)
- High-pressure homogenization in water
- Freeze-drying the final canister
- Autoclaving the dry powder
Correct Answer: Sieving and blending of drug with carrier (e.g., lactose)
Q38. Which statement is true: DPIs are generally characterized as:
- Non-pressurized, breath-actuated devices
- Pressurized with propellant gases
- Dependent on hand–breath coordination for dose release
- Requiring ethanol co-solvent for operation
Correct Answer: Non-pressurized, breath-actuated devices
Q39. Which excipient is commonly used in MDI suspensions to improve wettability and stability of the dispersed drug?
- Oleic acid (as a surfactant)
- Lactose
- Sodium chloride
- Cellulose powder
Correct Answer: Oleic acid (as a surfactant)
Q40. One major formulation challenge when converting a CFC MDI to an HFA MDI is:
- Different solvent properties of HFA requiring reformulation and use of co-solvents
- HFA being too similar to CFC making changes unnecessary
- HFA causing immediate chemical degradation of all drugs
- HFA creating insoluble salts with lactose
Correct Answer: Different solvent properties of HFA requiring reformulation and use of co-solvents
Q41. Increasing spacer volume generally has which effect on aerosol delivery?
- Reduces aerosol velocity and increases proportion of respirable dose
- Increases propellant strength and decreases lung deposition
- Makes particles larger by aggregation
- Converts suspension formulation to solution
Correct Answer: Reduces aerosol velocity and increases proportion of respirable dose
Q42. Which method is commonly used to measure emitted dose from an MDI in the lab?
- Filter collection at the mouthpiece followed by assay
- Visual colorimetry of plume only
- Measuring canister weight without actuation
- Using a Geiger counter for dose detection
Correct Answer: Filter collection at the mouthpiece followed by assay
Q43. What is the primary deposition mechanism for ultrafine particles (~0.5 µm) in the respiratory tract?
- Diffusion (Brownian motion)
- Inertial impaction
- Gravitational sedimentation
- Electrostatic attraction only
Correct Answer: Diffusion (Brownian motion)
Q44. How should a patient clean a typical DPI mouthpiece?
- Wipe with a dry cloth; avoid washing with water
- Rinse thoroughly under running water weekly and air dry
- Soak in ethanol daily
- Autoclave after each use
Correct Answer: Wipe with a dry cloth; avoid washing with water
Q45. Propellant density in an MDI formulation most directly affects which property?
- Suspension stability and spray characteristics
- Color of the emitted aerosol
- Lactose carrier adhesion
- Patient inspiratory effort
Correct Answer: Suspension stability and spray characteristics
Q46. “Shot weight” in the context of MDIs refers to:
- Mass of formulation released per actuation
- Total canister weight including propellant
- Mass of spacer attachment
- Weight of the powder capsule in a DPI
Correct Answer: Mass of formulation released per actuation
Q47. What MMAD range is generally considered optimal for deep lung (alveolar) deposition?
- 1–3 µm
- 5–10 µm
- 10–20 µm
- Greater than 20 µm
Correct Answer: 1–3 µm
Q48. Which factor most reduces DPI performance in real-world storage conditions?
- High humidity causing powder agglomeration
- Low ambient oxygen concentration
- Exposure to bright light only
- Placement on a metallic surface
Correct Answer: High humidity causing powder agglomeration
Q49. Which common user error requires the greatest coordination and therefore often reduces dose delivery accuracy?
- Using an MDI without coordinating actuation and inhalation
- Using a DPI with a rapid inhalation
- Using a spacer with an aerosol solution
- Shaking a suspension MDI before use
Correct Answer: Using an MDI without coordinating actuation and inhalation
Q50. For quality control of MDIs, which test specifically assesses the uniformity of delivered dose over the life of the canister?
- Delivered Dose Uniformity (DDU) testing
- pH stability test
- Moisture sorption isotherm
- Thermogravimetric analysis
Correct Answer: Delivered Dose Uniformity (DDU) testing
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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