Aerosols

Question 1

what are aerosols?

Answer 1

dispersion of fine particles or liquid droplets suspended in gas or vapor

Question 2

Rationale for inhaled drug delivery

Answer 2

Local delivery to site of action and delivery of systemically acting drugs.

Question 3

Inhaled drug delivery preferred over other forms of delivery

Answer 3

avoid systemic effects, rapid onset, no interaction with food, sterility, acceptability, avoid first pass metabolism and high absorption area.

Question 4

Advantages of aerosol drug delivery

Answer 4

avoid systemic effects, rapid onset, no interaction with food, sterility, acceptability, avoid first pass metabolism and high absorption area.

Question 5

Disadvantages of aerosol drug delivery

Answer 5

lungs generally designed to prevent inhalation of exogenous compounds, limitation of delivery of the drug (10%), irritation, taste, and reproducibility is a big concern.

Question 6

Is particle size important? and if so, what happens when particle size is too small or large?

Answer 6

Yes it is important.If size is too large or too small, it will not allow for it to reach the site of action.

Question 7

size range for aerosols

Answer 7

Aveolar region: 1 to 3 microns
trachea, bronchial, bronchiolar region: 3 to 10 microns
Higher up: 30 microns

Question 8

Methods to measure particle size

Answer 8

Microscopy
Sieving
Sedimentation
Electrical Resistance
Laser Diffraction
Aerodynamic diameter

Question 9

Advantages of PDMI

Answer 9

Portable, perceived easily to use and convenient, remaining product is not contaminated during use, can be filled asceptilly, stable, tamper proof, metered dose given.

Question 10

Disadvantages of PDMI

Answer 10

Expensive, pressurized contents (can be flammable) and prone to incorrect use.

Question 11

DPI advantages

Answer 11

no use of propellant gas, no hand eye coordination, easy to use and no spacer, dry powder form provides stability of drug, not pressurized container, lactose carrier particles mask bitter taste of drug

Question 12

DPI disadvantages

Answer 12

Sometimes bulky and non-portable, variable dose delivered dependent on inspiratory flow rates, not widely available, humidity protection, expensive, not all drugs available in this form.

Question 13

Nebulizer advantage

Answer 13

does not depend on pt. inspiratory force, used mainly as aq solns, do not have to hold their breath, and less expensive in the long run.

Question 14

Nebulizer disadvantage

Answer 14

Bulky/ not portable/ noisy, long treatment times, expensive, poorly optimized, contamination of the atmosphere, niche products.

Question 15

Propellants

Answer 15

provide pressure to expel product, act as dispersion medium, can exhibit solvent properties.

Question 16

Solvents

Answer 16

bringing active ingredient to soln, cosolvent for immiscible liquids, influence particle size, reduce vapor pressure.

Question 17

Chlorofluorocarbons (CFC)

Answer 17

low toxicity, high stability, good solvents

Question 18

Hydrofloroalkanes (HFA)

Answer 18

low toxicity, high stability, non-ozone depleting

Question 19

why do we not use CFC Propellants compared to HFA?

Answer 19

Global warming potential is six times less than HFA. Even though HFA is more expensive.

Question 20

Purpose of Surfactants

Answer 20

valve lubrication, aid in the dispersion of particles in suspension, stabilize foaming aerosols, emulsifying agents for emulsion aerosols, and decrease surface tension and particle size.

Question 21

Propellant Aerosol

Answer 21

drug is dissolved vs the gas aerosol where the drug is suspended or dispersed in the propellant system

Question 22

Gas Aerosol

Answer 22

better in the fact higher dosages can be delivered but Can be difficult to manufacture

Question 23

Propellant or gas, which one is better?

Answer 23

Probably propellant since its simplified manufacturing. Keep in mind though the drug needs to be soluable

Question 24

Inert carrier particles used in DPI

Answer 24

Lactose

Question 25

How to use A spacer

Answer 25

1. shake the medicine
2. Insert the mouthpiece of the inhaler into the rubber sealed end of the spacer
3. Breathe out. place spacer into mouth between your teeth. make a tight seal
4. Press the metered dose inhaler down to release a spray of medicine. the medicine will be trapped in the spacer. breathe deeply and slowly
5. hold breath for about 5 to 10 seconds and breathe out slowly

Question 26

Passive DPI

Answer 26

Dependent on pts inhalation to provide the energy needed to disperse the powder. Usually requires pt. to inhale at max rate to work properly. This determines the dose admin.

Question 27

Active DPI

Answer 27

Use of external energy source to generate power dispersion. Not dependent on pts efforts.

Question 28

Air Jet Nebulizers

Answer 28

Pressurized air

Question 29

Ultrasonic Nebulizers

Answer 29

Use high frequency vibration to generate the respirable aerosol, units compact/ generally high output, and quality of aerosol varies according to the energy supplied.