Inhalation Product Design and Testing

Question 1

what are the aims of inhalation drug delivery devices?

Answer 1

1. supply consistent drug delivery
2. high lung penetration
3. Multiple dosing facility
4. Minimise device size
5. Maximise patient convenience
6. Optimise drug actuation with minimal user effects

Question 2

what are some industrial and regulatory issues/challenges faced when designing the respiratory drug device?

Answer 2

1. inefficient delivery
2. cost of biomolecules
3. Formulation instability
4. Lack of licensed excipients
5. Inadequate screening tools
6. Multi-drug regimens
7. Patient acceptability

Question 3

what are some scientific issues/challenges faced when designing the respiratory drug device?

Answer 3

1. Formulation Instability
2. Poor site-specific targeting
3. Poor intracellular delivery
4. Toxicology & immunogenicity
5. Poor in vitro-in vivo correlation

Question 4

why are products tested?

Answer 4

to ensure they’re safe and effective

Question 5

what factors affect the safety and effectiveness of inhaled dosage forms?

Answer 5

1. the delivered dose
2. the aerodynamic particle size distribution of the dose
3. presence and possible inhalation of microbial contaminants
4. spray pattern or plume geometry of the device under test

Question 6

what is the role of ICH (international conference on harmonisation)?

Answer 6

• harmonises how each region (US,EU,China) regulates new drugs.
• enables new drugs to reach patients quickly and economically whilst maintaining safety, quality and efficacy

Question 7

what factors affect lung deposition of a drug?

Answer 7

1. formulation
2. device
3. patient factors
4. aerosol properties

Question 8

what is used to look at the size and shape of aerosol particles?

Answer 8

A transmission electron microscope (TEM)

Question 9

what tests are carried out for inhalables?

Answer 9

1. Uniformity of delivered dose
2. Fine particle dose
3. Aerodynamic particle size distribution
4. Effectiveness of antimicrobial preservative
5. Number of deliveries per inhaler
6. Leakage (pMDIs)

Question 10

what is the importance of measuring the uniformity of delivered dose?

Answer 10

-to ensure a consistency of the does emitted and the particle mass throughout the life of the container

Question 11

how do we test for uniform dose delivery?

Answer 11

• a dose collection apparatus containing a filter is used to see how much of the dose is sprayed out on use.
• more than 10 doses and more than 3 containers are tested from 2 different batches

Question 12

how do we calculate the active substance delivery rate?

Answer 12

mass of API on 1st filter divided by time interval for collection

Question 13

what is the fine particle dose/fraction?

Answer 13

the amount of the delivered dose that lies below the 5um cut-off size

Question 14

what does the aerodynamic particle size distribution determine?

Answer 14

where the API is deposited

Question 15

what type of particles are deposited at the lungs?

Answer 15

fine particles

Question 16

what the advantages of using inertial techniques to determine aerodynamic particle size?

Answer 16

1. helps differentiate between API and other formulations
2. measures aerodynamic diameter
3. provide the required degree of resolution in the particle size of interest

Question 17

how do cascade impactors work?

Answer 17

• separate particles on the basis of particle inertia (a function of velocity and aerodynamic particle size)
• doesn’t require knowledge of the particle shape or density