Routes of Administration - Inhalation

Question 1

Can you prescribe inhaler as a pharmacists?

Answer 1

You need to be an IP

Question 2

How to council patient to use an inhalier?

Answer 2

1. Remove cap (some must be squeezed at the sides to release)
2. Check dose counter (if device has one)
3. Hold inhaler upright and shake well
4. Breathe out gently (away frominhaler)
5. Put mouthpiece between teeth (without biting) and close lips to form good seal
6. Start to breathe in slowly through mouth and at the same timepress down firmly on canister
7. Continue to breathe in slowly and deeply
   8.Hold breath for about 5 – 10 seconds or as long as comfortable
8. While holding breath, remove inhaler from mouth
9. Breathe out gently (away from inhaler)
10. If more than onedose is needed, repeat all steps starting fromstep 3
11. Replace cap

Question 3

Emergency supply of salbutamol

Answer 3

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 4

What is pulmonary drug delivery?

Answer 4

provides a noninvasive, alternative method to subcutaneous injection, and also intravenous injection

Question 5

Pulmonary drug delivery; two routes

Answer 5

Local or topical drug administration

1] Asthma
COPD
Cystic fibrosis
Pulmonary hypertension
Lung infections?

2] Systemic application via the lung

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

Question 6

Systemic: Inhaled insulin

Answer 6

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

Question 7

How do we deliver drugs to or via the lungs?

Answer 7

Solid in gas: Solid particles suspended in air, e.g. smoke

Liquid in gas: Liquid particles suspended in air, e.g. mist

Gases

Question 8

But how do the solids/liquids/gases really get to where we want them to go?

Answer 8

It’s about engineering

Question 9

Anatomy of the mouth, throat and lung

Answer 9

a) Upper airways
b) Central/conducting airways
c) Respiratory/peripheral/pulmonary airways

Question 10

Upper airways

Answer 10

• Spheroidal sinus
• Middle turbinate
• Inferior turbinate
• Nasopharynx
• Oropharynx
• Larynx

Question 11

Central/conducting airways

Answer 11

• Trachea
• Main bronchus
• Large sub-segmental bronchus
• Small bronchus
• Bronchiole

Question 12

Respiratory/peripheral/pulmonary airways

Answer 12

• Terminal bronchiole
• Respiratory bronchiole
• Alveolar ducts and sacs

Question 13

Revise the structure of lungs

Answer 13

Label the lungs

Question 14

Branching of the lungs

Answer 14

Halving the radius produces 1600% increase in airflow resistance

• 1% decrease in diameter = 4% increase in resistance

Question 15

Airflow ________ with _______ branching.

Answer 15

decreases

increasing

Question 16

Difference between healthy adults and adults with diseases;

Answer 16

> healthy airway (clear diameter)
asthmatic airway - tight, shorter diameter, lining of the airways becomes swollen and inflamed
COPD airway - bronchial tubes become inflamed and narrowed and your lungs produce more mucus, which can further block the narrowed tubes

> healthy alveoli - effective for the blood exchange oxygen and carbon dioxide during the process of breathing in and breathing out
Alveoli with emphysema - the walls of the alveoli are partially destroyed

> Healthy airway - clear
Cystic fibrosis airway - filled with thick, sticky mucus, making it difficult to breathe

Question 17

Airflow in the lung is affected by the disease

Answer 17

• Obstructive lung disease
  Asthma
  COPD
  Cystic fibrosis
• Restrictive lung disease
  Interstitial lung disease, such asidiopathic pulmonary fibrosis
  Obesity

Question 18

What is the Drug delivery to the lungs?

Answer 18

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 19

Inertial impaction

Answer 19

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

Whether impaction occurs depends upon:
The particle’s momentum (dependent upon size!)
The position of the particle in the airstream of the parent branch
The angle of bifurcation (°θ)

Question 20

What is inertial impaction influenced by?

Answer 20

some degree by hyperventilation

Impaction is of significance for the largest particles moving at the highest speed in the respiratory tract

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

Question 21

Sedimentation meaning;

Answer 21

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 22

How is sedimentation influenced>]?

Answer 22

Breath-holding, allows more time for gravity to have an effect

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

Question 23

DIFFUSION
Which particles?
Minor mechanisms?

Answer 23

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

Minor mechanisms of deposition:
Interception for elongated particles
Charge reflection for charged particles

Question 24

Aerodynamic diameter
Equation - what each letter means?

Answer 24

dae = dg (ρ0.5)

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

Question 25

dae = Aerodynamic diameter

Answer 25

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

Question 26

Factors Influencing lung deposition

Answer 26

Particle size
Particle size distribution
Particle density
Particle shape
Particle hygroscopicity

Question 27

Deposition —> Absorption [upper airways]

Answer 27

Mucociliary escalator
(local drug concentration ↓ )

Drug dissolution
(local drug concentration ↑ )

Question 28

Deposition —> Absorption [alveolar region]

Answer 28

Macrophage clearance
(local drug concentration ↓ )

Translocation/efflux
(local drug concentration ↓ )

Question 29

Deposition —> Absorption [summary]

Answer 29

Dissolution > Clearance > Mucus direction > Phagocytosis > Translocation > To cells, blood 7 lymph

Question 30

Formulation Selection - Step by step
Beclomethasone dipropionate metered dose inhaler

Answer 30

1) Released (60%)
2) Deposited (20%)
3) Permeated (2%)
4) Efficacy (0.24%)

Question 31

Factors influencing lung deposition

Answer 31

Particle size
Particle density
Particle shape
Particle hygroscopicity
Propellants

Question 32

Inhaler types

Answer 32

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

Question 33

Quality control

Answer 33

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

Question 34

Advantages of local delivery of drugs to the lungs

Answer 34

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 35

Disadvantages of local delivery of drugs to the lungs

Answer 35

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 36

Advantages of systemic delivery of drugs via the lungs

Answer 36

Very rapid onset of action
Circumvents first pass effect
Non-invasive delivery route
Good for biopharmaceuticals

Question 37

Disadvantages of systemic delivery of drugs via the lungs

Answer 37

Low efficiency of delivery
Some patients may have difficulty using some devices (handling and coordination)
Some patients may have difficulty breathing (through the device)
May need very low or very exact doses or special devices
Expensive compared with oral therapies

Question 38

OTC inhalator

Answer 38

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

Question 39

How to use Nicorette inhalator?

Answer 39

1) Line up the markers and pull each end in the opposite direction

2) Insert the cartridge into the mouthpiece and twist to close securely

3) 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