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Flashcards in Inhaled Route Deck (16)
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1

What kind of conditions requires inhaled drug delivery?

airway diseases like asthma

2

Advantages of inhaled route: (4)

- 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

3

Disadvantages of inhaled route: (4)

- 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

4

Inhaltion drug delivery requires the formulation to be...

aerosol

5

What is a pharmaceutical aerosol?

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

6

The fate of particles in the airways (3)

Deposition
Dissolution
Absorption

DDA

7

Patient factors affecting particle deposition: (2)

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

lung physiology e.g. lung capacity / diseases

8

Phsyicochemical factors affecting particle deposition:

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

Shape and physical stability of particles

9

3 main mechanisms responsible for drug deposition:

intertial impaction
gravitational sedimentation
brownian diffusion

10

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

drug deposition in the lung

11

An aerosolised drug powder must first dissolve in the...

mucus layer before absorption

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

12

How are particles deposited in the ciliated conducting airways cleared?

by mucociliary clearance within 24 hours are swallowed with the mucus

13

Particles deposited into the alveolar region are cleared by...

macrophages

14

Drug absorption can only take place if...

dissolution is faster than clearance

15

How are hydrophobic materials absorbed?

at a rate dependent on their oil/water partition coefficients

16

How are hydrophilic compounds absorbed?

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