Inhaler Performance

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  • Created by: LBCW0502
  • Created on: 16-03-19 15:29
Which model is used to test aerosol performance? (1)
Twin stage impinger (illustration of the lungs). Larger particles deposited in mouth/upper airways. 6-8 microns deposited in bronchioles. Smaller particles deposited in lower airways. Inhaler attached. Pump generates flow rate
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Which model is used to test aerosol performance? (2)
After actuation, turn off pump, take apparatus apart and use analytical methods to measure the particle concentration in each region e.g. HPLC, UV (high concentration, highly sensitive), MS (low concentration)
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How do you calculate recovered dose (%)?
Drug recovered from packaging + inhaler + evaluation device (mg/mcg) / original drug dose (mg/mcg) x 100 = RD%, needs to be 90% or more (validation)
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How do you calculate the total emitted dose (%)?
Drug recovered from packaging + inhaler + evaluation device (mg/mcg) / recovered dose (mg/mcg) x 100 = ED% (between 90 and 110%, clogging/agglomeration, device caking, different actuation/dose). Need RD and ED to be similar (same dose)
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How do you calculate fine particle fraction (fine particle dose, respirable dose)? (1)
(% < 5 microns). Amount of particles in respirable range (1-5 microns). Particles <6.4 microns in lower region of twin stage impinger. Cascade impactor (5-7 filters) used for testing. Next generation impactor - sieves with holes (different sizes)
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How do you calculate fine particle fraction (fine particle dose, respirable dose)? (2)
Drug recovered from TSI lower chamber or ACI stages 3-7 + filter (mg/mcg) / recovered dose (mg/mcg) x 100 = FPF%
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What is mass median aerodynamic diameter? (1)
MMAD (micrometres). Median particle size of a log normal particle size distribution curve derived from mass of drug depositing on each stage of ACI, NGI or MLI. Want log normal distribution with more smaller particles in lungs
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What is mass median aerodynamic diameter? (2)
(if normal distribution, large particles will not reach lower lungs and small particles will be removed when exhaling)
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How do you calculate the geometric standard deviation?
GSD = square root of 84% undersize value (micrometres)/16% undersize value (micrometres). Expressed with MMAD
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Outline features of the twin stage impinger
Illustrates the lungs - mouth and throat, trachea and upper airways, lower airways (respirable dose)
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Outline features of the multi-stage liquid impinger (1)
Contains liquid chambers (particles can bounce e.g. if particles are deposited due to being too heavy it might bounce back or trapped in liquid e.g. mucus, clear layer, particle may stay where it lands)
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Outline features of the multi-stage liquid impinger (2)
Grow epithelial cells (simple model to see interactions)
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Outline features of the Anderson cascade impactor
No liquid used, heavy particles may bound in airflow. Use of sieves to see the number of fine particles reaching lower regions
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Outline features of the new generation impactor
Filters, particles deposit in plates depending on size, measure drug distribution
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Is the geometric diameter or aerodynamic diameter is more important?
Aerodynamic diameter - (smaller diameter, density increases, affects movement of particles). Possible to have larger/light particles or smaller/heavier particles
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What are the BP required tests?
Uniformity of delivered dose, aerodynamic assessment of fine particles. 9-10 actuations 75-125% of mean value to pass
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Why does the emitted dose not add up to 100%?
Particles may escape through exhalation or particles removed by mucus etc.
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Other cards in this set

Card 2

Front

Which model is used to test aerosol performance? (2)

Back

After actuation, turn off pump, take apparatus apart and use analytical methods to measure the particle concentration in each region e.g. HPLC, UV (high concentration, highly sensitive), MS (low concentration)

Card 3

Front

How do you calculate recovered dose (%)?

Back

Preview of the front of card 3

Card 4

Front

How do you calculate the total emitted dose (%)?

Back

Preview of the front of card 4

Card 5

Front

How do you calculate fine particle fraction (fine particle dose, respirable dose)? (1)

Back

Preview of the front of card 5
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