inhaled medicine

Question 1

what is the physical purpose of airways?

Answer 1

to humidify and heat the air inhaled
remove particles in air inhaled
to clear deposited particles into the GI tract
particles shouldn’t reach the alveoli

Question 2

why is taking an inhaler delivered to the lung?

Answer 2

via respiratory tract for local and systemic effect
‘rapid onset of action’
comfortable to take
the doses are smaller than oral doses so less systemic and GI adverse tract

Question 3

how are barriers for delivery and to penetrate airways overcome?

Answer 3

drugs delivered int eh form of aerosol

Question 4

what is aerosol?

Answer 4

suspension of liquid or solid particles in gas

Question 5

what makes an aerosol particle effective?

Answer 5

deposits int he appropriate region in the lung
overcomes physiological barriers
right quantity of drug

Question 6

what is stoke’s law equation?

Answer 6

don’t need to remember equation:
slide 7

Question 7

relationship between viscosity and velocity in strokes law?

Answer 7

as viscosity goes up the velocity goes down

Question 8

what is the equation of aerodynamic diameter?

Answer 8

don’t need to remember this:
slide 7

Question 9

what size do particles need to be?

Answer 9

particles need to be less than 10 microns to get into lungs

Question 10

what is the defintion of the respirable fraction of an inhaled medicine?

Answer 10

‘percentage present in aerosol particles less than 5 micrometres so less likely to be deposited’

Question 11

what devices can be used to stimulate inhalation process?

Answer 11

Anderson Cascade Impacter
Next Generation Impinger

Question 12

how does the NGI work?

Answer 12

7 stages
calibrated to flow rate required
powder is collected in cups
size distribution is a prediction of site of deposition of drugs in the lungs

Question 13

what are the three types of inhalers?

Answer 13

Nebulisers
Pressurised metered dose inhalers (pMDI)
Dry powder inhalers (DPI)

Question 14

how does nebeulisers work?

Answer 14

aqueous drug with energy supplied by compressed air

Question 15

how does pMDI work

Answer 15

liquified ga under pressure
aerosol formed by evaporation of gas

Question 16

how does the DPI work?

Answer 16

dry powder delivered
no solvent
deliveries a large dose compared to pMDI
breath actuated
drug in dry form more stable than drug in solvent

Question 17

how is the dose in pMDI aquired?

Answer 17

when pMDI pressed down only liquid in metering chamber is released

Question 18

why does an inhaler get shook before use?

Answer 18

because metering chamber needs to be filled
to make sure no settling of particles and drug is distributed

Question 19

when is a spacer device used?

Answer 19

with patients with poor coordination

Question 20

what are the problems with DPI?

Answer 20

dose delivery and deposition depends on patients inspiratory flow rate
particles less than 5 micrometres are needed to enter the lung but are cohesive
moisture causes agglomeration

Question 21

what are the solutions for issues with DPI?

Answer 21

spherical particles reduce aggregation
protected form moisture
drug blended with carrier particle that are larger particles so drug has to be separated before inhalation

Question 22

what are the types of DPI?

Answer 22

unit dose devices
multiple unit dose devices
reservoir devices

Question 23

what is the formulation of DPI?

Answer 23

ordered mix-carrier particles used to stop small particles form aggregating
small particles have to be separated from carrier particles before inhalation
drug is deposited in the lungs