Pulmonary Drug Delivery II

Question 1

What addition to the inhaler is there for children?

Answer 1

A valved holding chamber (spacers) +/- facemask is often used

Question 2

What is special about the valve in the spacer?

Answer 2

‘one-way’ valve, only allowing pressure towards the mouth and NOT back in

Question 3

pMDIs and special patient groups

Answer 3

Spacers do not require the patient to coordinate their breathing with the actuation of the pMDI

Question 4

________ the initial droplet velocity and allows time for propellant to evaporate

Answer 4

reduces

Question 5

What issues might patients face using inhalers?

Answer 5

Patients with limited dexterity, e.g. arthritis

Partially-sighted patients or with reduced vision

Patients with cognitive impairment

Elderly – lung function reduces over time (a problem for DPI use)

Question 6

What may patient facing issues with inhalers benefit from?

Answer 6

spacer or potentially breath-actuated pMDIs or nebulizer therapy

Question 7

Examples of Breath-actuated pMDIs?

Answer 7

Easyhaler, Autohaler, Easi-Breathe, assist with coordination of inspiration and actuation

Question 8

What does INSPIRATION by the patient trigger?

Answer 8

the release of the drug, i.e. opening of the metering chamber

Question 9

Dry powder inhalers (DPIs)

Answer 9

use no propellant and rely on the force of the patient’s inspiration to carry the drug (as a dry powder) into the lungs

Question 10

List the two common categories of DPIs?

Answer 10

1. Drug in hard capsule DPIs
2. Multidose DPIs (multiple unit dose OR reservoir type)

Question 11

What are the advantages of DPis?

Answer 11

• Propellant free, i.e. better for the environment than pMDIs
• Being breath-actuated they avoid inspiration and actuation coordination issues
• Can deliver larger doses of drug than pMDIs

Question 12

What are the disadvantages of DPIs?

Answer 12

• DPIs require inspiratory flow rates of 30-90 L/minute
• Sometimes a higher upfront cost
• DPIs more exposed to ambient air which may cause stability issues

Question 13

Drug particles should be <___ um for biopharmaceutical reasons&raquo_space;> need to be micronized

Answer 13

5um

Question 14

Micronization:

Answer 14

process of reducing drug particle size to micron size ranges (typically <5 m in diameter)

Question 15

Micronized particles often have _____ flow properties due to static / cohesive / adhesive nature

Answer 15

poor

Question 16

Drug (micronized) particles mixed with much larger (30 um to 150 um) carrier particles to ______ flow

Answer 16

improve

Question 17

smaller the particles the ______ the flowability, why?

Answer 17

worse

the particles form electrostatic interaction between each other which effects on the flow

Question 18

Process of DPi

Answer 18

1) patient breathes in
2) pressure into the turban
3) larger particles will stay in the mouth
4) smaller particles will go down the airways and into the lungs

Question 19

DPI capsule, what is the shell made out of?

Answer 19

hard-shelled gelatin capsule

Question 20

STEP BY STPE OF USING A DPI CAPSULE (1)

Answer 20

1) Capsule is loaded into the device by the patient

2) Punctured by two metal needles inside the device

3) Inspiration by the patient causes a rotor to rotate andthis causes a turbovibratory air pattern to disrupt thepowder in the capsule

Question 21

MULTIDOSE DPIs (2), what are the 2 categories?

Answer 21

Multiple unit dose device
Reservoir-based device

Question 22

What are Smart inhalers?

Answer 22

Smart inhalers use sensors in thedevice to detect and record on the use of the inhaler

Question 23

How do smart inhalers work?

Answer 23

inhaler connects via Bluetooth to a smartphone or other device and (should the patient choose to) their data can be shared with the prescriber/ asthma specialist

Question 24

What data does the smart inhaler gather?

Answer 24

How often the device is use
Inspiratory flow rate (important for a DPI)

Question 25

What are Nebulizers?

Answer 25

much larger pulmonary delivery devices that generate aerosols from the contents of unit dose nebules

NOT PORTABLE - size and power requirements

Question 26

how are nebulisers used?

Answer 26

inhaled during NORMAL breathing usually via a mask

used in hospital and domiciliary settings

Question 27

What is the formulation of Nebules?

Answer 27

drug dissolved in “normal saline”

Question 28

Normal saline is a ____% w/v NaCl aqueous solution

Answer 28

0.9%

Question 29

Venolin Nebules
= solution
What excipients?

Answer 29

• NaCl
• Sulphuric acid if required to adjust pH
• Purified water

Question 30

Flixotide = suspension

Answer 30

a number of surfactants need to be used to keep it homogenous and stable

Question 31

Jet Nebulizers, what do they require?

Answer 31

compressed air from a cylinder, hospital air line or electrical compressor

Question 32

Jet Nebulizers, what is the drug delivery determined by?

Answer 32

Aerosol droplet size and drug delivery is determined by the compressed gas flow rate

Question 33

Jet nebulizer: Compressed air passed through the _______ nozzle – low pressure created draws liquid up from the reservoir through a feed tube

Answer 33

Venturi

Question 34

Jet nebulizer, what is the role of the ‘Baffle’?

Answer 34

ensures that (larger) non-respirable particles are not inhaled and can be recycled

Question 35

Ultrasonic Nebulizers’s role:

Answer 35

Energy to generate aerosol comes from a vibrating piezoelectric crystal

Question 36

Ultrasonic Nebulizers’s
Diagram (on pp) LABEL

Answer 36

Piezoelectric transducer = chemical energy to mechanical energy > sound waves

reaches the diaphragm and reaches the aerosol chamber where gas is fed in and aerosol goes out

Question 37

Mesh Nebulizers

Answer 37

may have up to 7000 holes etched with a laser

Question 38

How do mesh nebulizers work?

Answer 38

Vibrational energy due to a piezoelectric crystal which transfers energy to the mesh via a transducer

(Newer designs are able to coincide aerosol release with the patient’s breathing > reducing drug wastage)