Routes of Administration: inhalation

Question 1

What is the emergency supply of salbutamol?

Answer 1

In an emergency, as a pharmacist working in a registered retail
pharmacy, you can supply prescription-only medicines (POMs) without
a prescription at the request of a relevant prescriber or a patient

Question 2

What are the two routes to pulmonary drug delivery?

Answer 2

*local or topical drug administration
*systemic application via the lung

Question 3

What are local pulmonary drug administrations used to treat?

Answer 3

• Asthma
• COPD
• Cystic fibrosis
• Pulmonary hypertension
• Lung infections?

Question 4

What are systematic applications via the lung used to treat?

Answer 4

• CNS stimulation
• Anaesthetics
• Diabetes
• Pain and migraine
• Appetite suppression

Question 5

What have been the downsides to systemic: inhaled insulin?

Answer 5

Because of the route of
administration, many
respiratory adverse effects
were reported, including
increased risks of
respiratory infection,
cough, pharyngitis, and
rhinitis.

Question 6

How does airflow differ with different branching?

Answer 6

Airflow decreases with increased branching

Question 7

What are the types of lung disease?

Answer 7

*obstructive lung disease
*restrictive lung disease

Question 8

What are some obstructive lung diseases?

Answer 8

Asthma
* COPD
* Cystic fibrosis

Question 9

What are some restrictive lung diseases?

Answer 9

• Interstitial lung disease, such
  as idiopathic pulmonary fibrosis
• Obesity

Question 10

How are drugs delivered to the lungs?

Answer 10

Particles entering the respiratory tract are prevented from reaching the
terminal bronchioles and alveoli by mechanisms which cause them to be
caught by the mucous sheath lining the tubules

Question 11

When does inertial impaction happen?

Answer 11

Inertial impaction tends to occur in the upper airways when the velocity
and mass of the particles cause them to impact the airway surface

Question 12

What does impaction depend on?

Answer 12

• The particle’s momentum (dependent upon size!)
• The position of the particle in the airstream of the parent branch
• The angle of bifurcation (°θ)
  *can be influenced to some degree by hyperventilation

Question 13

How does particle size impact chance of impaction?

Answer 13

• 10 μm particle has a 50% chance of impaction
• 5 μm – 20%
• 3 μm – 10%
• 1 μm – 1%

Question 14

What is sedimentation dominant for + how are particles suspended?

Answer 14

• Particles suspended in a gas are subject to the vertical gravitational
  force
• Sedimentation is the dominant mechanism for particles depositing in the
  lower/peripheral airways

Question 15

What is sedimentation influenced by?

Answer 15

• Tends to be influenced by breath-holding, which allows more time for
  gravity to have an effect

Question 16

How does particle size affects % of sedimentation?

Answer 16

• Important for particles 0.5 μm < daero < 5 μm
• 2 μm – 55%
• 1 μm – 29%
• 0.5 μm – 10%

Question 17

What is diffusion + how does particle size affect this?

Answer 17

• Diffusion = dominant mechanism for particles < 0.5 μm
• The smaller the particles, the more they deposit via diffusion in the
  peripheral lung and alveolar space

Question 18

What are some minor mechanisms of deposition?

Answer 18

• Interception for elongated particles
• Charge reflection for charged particles

Question 19

What is an aerodynamic diameter?

Answer 19

Diameter of a sphere with the same terminal velocity
in air or some other relevant fluid as the particle

Question 20

What is the aerodynamic equation?

Answer 20

• Aerodynamic diameter (dae) is dependent on the geometric diameter
  (dg), shape factor (1 for spheres) and density (ρ) of the particle

Question 21

what factors influence lung deposition?

Answer 21

• Particle size
• Particle size distribution
• Particle density
• Particle shape
• Particle hygroscopicity

Question 22

How does deposition differ from absorption (upper airways)?

Answer 22

deposition:
*mucociliary escalator (local drug concentration ↓)

absorption:
*drug dissolution (local drug concentration ↑)

Question 23

How does deposition to absorption differ in (alveolar region)?

Answer 23

deposition:
*macrophage clearance (local drug concentration ↓)

absorption:
*translocation/efflux (local drug concentration ↓)

Question 24

What is the formulation selection breakdown of a beclomethasone dipropionate metered dose inhaler?

Answer 24

released: 60%
deposited: 20%
permeated: 2%
efficacy: 0.24%

Question 25

What are the different inhaler types?

Answer 25

• Pressurized metered-
  dose inhaler + (spacer)
• Accuhaler / Diskus
• Handihaler
• Respimat
• Turbohaler
• (Nebuliser)

Question 26

What is entailed in quality control?

Answer 26

• Deposition of emitted
  dose
• Content uniformity
• Aerodynamic particle
  size distribution
• Spray pattern

Question 27

What are the advantages of local delivery of drugs to the lungs?

Answer 27

• Drug delivered directly to target organ
• Lower doses may be required for optimal effect
• Rapid onset of action
• Fewer systemic side effects
• Non-invasive delivery

Question 28

What are the disadvantages of local delivery of drugs to the lungs?

Answer 28

• Low efficiency of delivery
• Difficulty in breath coordination, manual handling of device, or
  breathing through the device
• Corticosteroid use can suppress immune response
• Throat irritation is possible

Question 29

How does an OTC inhalator work?

Answer 29

• When a patient draws air into the mouth through the mouthpiece,
  nicotine is vaporised and absorbed by the buccal mucosa into the
  bloodstream

Question 30

How do you use a Nicorette inhalator?

Answer 30

• Line up the markers and pull each end in the opposite direction
• Insert the cartridge into the mouthpiece and twist to close securely
• When you have a craving take a shallow puff about every 4 seconds
  or take 2 deep puffs every minute. Each cartridge lasts for
  approximately 40 minutes of frequent puffing