Inhalation Product Design Flashcards

1
Q

What must be considered in inhaler design?

A

Right dose delivered
Aerodynamic particle
Patient + clinician acceptability
Cost
Ease of use

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2
Q

What is the most suitable particle size?

A

2-5 micrometer

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3
Q

What are the scientific challenges?

A

Poor site targeting
Poor intracellular delivery
Toxicology
Poor in vitro-in vivo correlation
Formulation instability

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4
Q

What does in vitro study determine?

A

Performance in a controlled environment outside of a living organism

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5
Q

Describe the process for designing a new inhalable

A

Fully characterised drug formulation
Device selection
Dose retrieval
Characterisation post aerosolisation
Bioactivity pre/post aerosolisation
Breathing simulator studies
In vitro bioactive inhaled therapeutic
In vivo studies

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6
Q

What are the BP tests for inhaler devices?

A

Uniformity of delivered dose
Fine particle dose
Aerodynamic particle size distribution
Number of deliveries per inhaler
Effectiveness of antimicrobial preservative
Leakage (pMDIs)

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7
Q

What does the uniformity of delivered dose ensure?

A

Consistency of the dose emitted + fine particle mass throughout the life of container form

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8
Q

What do DPIs rely on?

A

Patient’s inspiratory flow rate than propellant for dose emission

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9
Q

What is fine particle dose?

A

Amount of delivered dose that lies below 5 micrometre cut-off

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10
Q

How is fine particle dose determined?

A

In parallel to aerodynamic particle size distribution

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11
Q

What does aerodynamic particle size distribution determine?

A

Where the API is deposited

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12
Q

What is the fraction that is deposited in the lung referred as?

A

Fine particle fraction (FPF)

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13
Q

What is the optimal size for peripheral airway deposition?

A

Upper limit = 5 micrometre
Lower limit = 1 micrometre

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14
Q

How do cascade impactors work?

A

Comprise a series of progressively finer jets + collection plates
Separate particles on basis of particle inertia

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15
Q

Describe cascade impactor operation

A

Samples drawn into impactor flowing
Nozzle size + area decrease with stage number
Particles remain or break through lines of flow
Particles with sufficient inertia collected rest pass on to next stage

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16
Q

What are the different cascade impactor designs?

A

Glass impinger
Multi-stage liquid impinger (MSLI)
Andersen cascade impactor (ACI)
Next generation impactor (NGI)

17
Q

What are glass impingers used to test?

A

pMDIs
DPIs
Nebulisers

18
Q

What is problem with glass impingers?

A

Limited info regarding particle size
= 2 stages

19
Q

Particles collected in throat of glass impinger considered?

A

“Non-respirable” = NOT inhaled into lower respiratory tract

20
Q

Particles collected in lower impinger considered?

A

“Respirable”

21
Q

What does MSLI test?

22
Q

Describe MSLI

A

4 stages with filter terminal

23
Q

How are the collection stages kept in MSLI?

A

Moist
= eliminates particle bouncing off the collection plate

24
Q

Describe ACI

A

8-stage cascade impactor

25
What does the ACI test?
MDIs DPIs
26
What are the advantages of ACI?
Easy to handle stack-up design Damaged stages can be replaced
27
Describe NGI
Cups rather than plates 7-stages
28
What rate does NGI operate between?
15-100 L/min flow rates
29
What does the NGI test?
pMDIs DPIs Nebulisers
30
Describe the number of deliveries per inhaler BP test
Take an inhaler + discharge the contents to waste until empty
31
What are the requirements of number of deliveries per inhaler BP test?
Total number of deliveries discharged from inhaler must not be less than number stated on product label
32
Describe the efficacy of antimicrobial preservative BP test
Preservative properties adequate = significant fall or no increase in number of micro-organisms
33
What is the formulation for leakage pMDIs BP test?
Solution/suspension
34
What is the requirement for the leakage pMDIs BP test?
Not more than 10% of the nominal fill mass of the container over entire shelf life
35
What is used in uniformity of delivered dose test + why?
Critical flow controller to allow adjustable flow + inhaled vol
36
Why is breathing pattern important?
Determines amount of API available for the patients
37
What is the uniformity of delivered dose test based on?
Standardised tidal flow conditions generated by breath simulator