pMDIs and special patient groups

Question 1

pMDIs and special patient groups

Answer 1

• Ability of a patient to use a pulmonary drug delivery device needs to be considered
• A valved holding chamber and spacer used with young children

Question 2

Why are spacers benificial

Answer 2

• Do not require the patient to coordinate their breathing
  with the actuation of the pMDI
• Reduce intial droplet velocity allows time for propellant to evaporate

Question 3

Structure of spacer

Answer 3

• One way valve
• Cap removed and patient inhales through
• pMDI mouthpiece

Question 4

Patients that would use a spacer

Answer 4

• Patients with limited dexterity, e.g. arthritis
  – Partially-sighted patients or with reduced vision
  – Patients with cognitive impairment
  – Elderly – lung function reduces over time

Question 5

Alternative therapy that can be used for specific patient groups

Answer 5

Breath-actuated pMDIs or nebulizer therapy

Question 6

Young infant using inhaler

Answer 6

• Nebulizer + mask may be used

Question 7

Breath-actuated pMDIs

Answer 7

• Easyhaler, Autohaler, Easi-
  Breathe
• Inspiration by the patient triggers the release of drug

Question 8

Dry powder inhalers

Answer 8

• DPIs use no propellant and rely on the force of the patient’s
  inspiration to carry the drug

Question 9

Two types of DPIs

Answer 9

• Drug in hard capsule DPIs
• Multidose DPIs

Question 10

Advantages of DPI

Answer 10

• Propellent free better for environment
• Being breath-actuated avoid inspiration and actuation coodination issues
• Can deliver larger doses of drug that pMDI

Question 11

Disadvantage of DPI

Answer 11

• DPI requires insiratory flow rate of 30-90 l/mim
• Higher upfront cost
• DPI more exposed to ambient air which may cause stability issues

Question 12

Formulation of DPIs

Answer 12

• Drug should be <5 mcg for biopharmaceutical reasons need to be micronised

Question 13

Micronisation process

Answer 13

• Milling/ Grinding
• Spray drying
• Spray freeze drying
• Supercritical fluid processes

Question 14

Properties of Micronized particles

Answer 14

• Poor flow properties due to static / cohesive / adhesive nature
• Drug mixed with carrier to improve flow
• Lactose typically used for carrier particles

Question 15

Lactose and micronised particles adherance

Answer 15

• Formulated so that micronized drug particles adhere to the larger lactose particles
• Leads to more uniform device filling and improved liberation of drug from the DPI
• Turbulent airflow causes the drug particles and carrier particles to disaggregate

Question 16

Drug in hard capsule DPIs

Answer 16

• Drug in hard capsule DPIs
• Capsule is loaded into the device by the patient
• Punctured by two metal needles inside the device
• Inspiration by the patient causes a rotor to rotate and this causes a turbovibratory air pattern to disrupt the powder in the capsule

Question 17

Multidose DPIs

Answer 17

• Diskhaler or Accuhaler

Question 18

Reservoir based inhaler

Answer 18

• Requires initial click
• Only one reservoir may have stability issues
• Clickhaler and Turbohaler

Question 19

Smart inhaler

Answer 19

• Sensor device. Detect and record on the use of inhaler
• Connects via Bluetooth to a smartphone and device
• GoResp Digihaler DPI contain Budesonide
  -Records data how often used and inspiration flow

Question 20

Nebuliser

Answer 20

• larger pulmonary delivery devices generate aerosol from the contents of unit dose of nebules
• Large vol of drug solution
  -Drug inhaled during normal breathing
• Used in hospital not portable due to size

Question 21

Formulation of nebules

Answer 21

• Dissolved in normal saline (0.9% w/v NaCl aqueous solution)
• purified water
  -Sulphuric acid

Question 22

Steroid nebules suspension formulation

Answer 22

• Has polysorbate surfactant
• Sorbitan laureate
• Water for injection
• NaCl

Question 23

Jet nebuliser

Answer 23

• Require compressed air from cylinder or electrical compressor
• Aerosol droplet size determined by compressed gas flow rate
• Baffle ensure that large non respirable particles are not inhaled
• Compressed air passed through the venturi nozzle - low pressure cause draws up liquid from reservoir

Question 24

Ultrasonic Nebuliser

Answer 24

• Large aerosol droplets are emitted from the apex and smaller droplets from the
  lower areas
• Energy to generate aerosol comes from a vibrating piezoelectric crystal