Inhaled Route

Question 1

What kind of conditions requires inhaled drug delivery?

Answer 1

airway diseases like asthma

Question 2

Advantages of inhaled route: (4)

Answer 2

• smaller doses can be used - reduces side effects and costs
• rapid absorption (large surface area, high vascular surface, thin air-blood barrier)
• avoids harsh GI environment and degradation
• avoids hepatic first-pass metabolism

Question 3

Disadvantages of inhaled route: (4)

Answer 3

• complex delivery devices meaning high costs
• aerosol devices can be difficult to use
• mucus layer limits absorption, mucociliary clearance reduces retention time
• local side effects

Question 4

Inhaltion drug delivery requires the formulation to be…

Answer 4

aerosol

Question 5

What is a pharmaceutical aerosol?

Answer 5

two-phase system of solid particles or liquid droplets dispersed in the air. Very small size particles

Question 6

The fate of particles in the airways (3)

Answer 6

Deposition
Dissolution
Absorption

DDA

Question 7

Patient factors affecting particle deposition: (2)

Answer 7

breathing patterns - the larger the inhaled volume, the greater the peripheral distribution of particles

lung physiology e.g. lung capacity / diseases

Question 8

Phsyicochemical factors affecting particle deposition:

Answer 8

the aerodynamic size of the drug particle (which depends on physical size and density)

Shape and physical stability of particles

Question 9

3 main mechanisms responsible for drug deposition:

Answer 9

intertial impaction
gravitational sedimentation
brownian diffusion

Question 10

There is an upper size and lower size limit effective for…

Answer 10

drug deposition in the lung

Question 11

An aerosolised drug powder must first dissolve in the…

Answer 11

mucus layer before absorption

once in, it will diffuse through the mucus layer and enter the aqueous environment of the epithelial lining liquid

Question 12

How are particles deposited in the ciliated conducting airways cleared?

Answer 12

by mucociliary clearance within 24 hours are swallowed with the mucus

Question 13

Particles deposited into the alveolar region are cleared by…

Answer 13

macrophages

Question 14

Drug absorption can only take place if…

Answer 14

dissolution is faster than clearance

Question 15

How are hydrophobic materials absorbed?

Answer 15

at a rate dependent on their oil/water partition coefficients

Question 16

How are hydrophilic compounds absorbed?

Answer 16

poorly absorbed through membrane pores at rates inversely proportional to molecules size