Aerosols Flashcards
Name 3 respiratory conditions inhalation therapy is commonly indicated for.
- Asthma
- COPD
- Cystic fibrosis
Compressed gas propellants are used mostly for what type of prep?
Topical preparations
What determines droplet size in ultrasonic nebulizers?
Frequency of the sound waves
This product concentrate contains the API dissolved in the pure propellant.
Solution system
How is the medication formulated in nebulizers?
Medication is diluted in a reservoir (nebulizer unit)
What’s an inhalant?
Drug with high vapor pressure that can simply be inhaled through the nose
Types of product concentrate that can be found in the aerosol fmlation of pressurized devices?
- Solution systems (two-phase system)
- Suspension systems (two-phase system)
- Emulsion systems (three-phase system)
Three mechanisms of inhaled particle deposition?
- Inertial impaction (>5 µm)
- Gravitational sedimentation (ideal - 0.5 - 5 µm)
- Brownian diffusion (<0.5 µm)
What is necessary for the components of an aerosol container?
a. Chemically inert
b. Able to withstand numerous actuations
Most common type of drug delivered via nebulizers?
Non-steroidal asthma meds
Why is a mouthpiece preferable to a face mask?
Drugs delivered by face mask come into contact w/ the face’s skin.
Jobs of the propellant? (3)
- Develop proper pressure in container
- Expel product
- Aid in atomization or foam production
Approx how lg are aerosol particles (solid or liquid particles)
<50 µm
Do we want partial solubility of API in the propellants of suspension systems?
NO! This will lead to inaccurate dosing via precipitation and possible Ostwald ripening.
Nebulizer therapy is most commonly used for what? (5)
- Emergency treatment for acute asthma and COPD
- long-term bronchodilation for chronic airflow obstruction
- Asthma prophylactic
- Antibiotics for cystic fibrosis, bronchiectasis, and HIV/AIDS
- Palliative care related to airways/lungs
Advantages of nebulizers? (4)
- No coordination needed
- No strong flow needed to deliver dose
- good lung penetration
- Can be used w/ young children or pts unable to receive other aerosol dosage forms
Two types of aerosol devices?
- pressurized devices
2. non-pressurized devices
What’re the two methods of filling aerosols?
- Cold fill
2. Pressure fill
What is the most common goal of inhalation therapy?
Bronchodilation (via aerosols)
Is vapor pressure constant with CFC/HFA/HC propellants?
Yes
What physics phenomenon allows jet nebulizers to work?
Venturi effect
What type of preps are usually used w/ continuous valves?
topical
Desirable spray features? (3)
Focused spraying
Uniform spraying
Easy to press
Name 2 inhalation device aids.
- Spacers
2. Counters
Advantages of DPIs? (5)
- No coordination of actuation and inspiration req’d
- Cold air doesn’t affect it
- Device can be checked to make sure if full dose was inhaled
- Pt. my inhale repeatedly to ensure full dose is received
- No propellants/CFCs
How does a nebulizer work?
Liquid med is aerosolized by a compressor
Where do inhaled particles that’re larger than 5µm end up?
Upper airways (oropharynx)
Ozone depleting propellant?
CFC
What causes aerosolization in ULTRASONIC nebulizers?
Ultrasonic waves
What’s an aerosol
Pharmaceutical preparation in devices UNDER PRESSURE
This type of propellant is used in foam and water-based aerosols only
HC
Name the respiratory structures. (5)
- nasal cavities
- pharynx
- treachea
- bronchi
- alveoli
What’s an inhalation?
Drug that’s given via respiratory route
Why might DPIs be a problem for older pts?
They’re unable to inspire deeply.
Is rapid inhalation or slow, steady inhalation preferred in inhalation therapy?
Slow, steady inhalation > this increases the # of particles that’ll penetrate the peripheral portions of the lung
What causes aerosolization in JET nebulizers?
Compressed air/O2
This product concentrate contains the API dispersed in the propellant
Suspension system
Outline how CFC/HFA/HC propellants cause the expulsion of drug from the aerosol canister.
- Eqlm b/w liquified propellant and its vapour
- actuator pressed > vapour pressure pushes liquid up dip tube
- release of drug and propellant (liq) through orifice into atmosphere
- liq propellant in air evaps instantly, leaving airborne liquid droplets or dry particles
- In canister, vapor pressure eq’lm is re-established when some of liq propellant becomes vapor
What’re the two types of valves used with aerosol containers?
Continuous and metred
The container of aerosols can be made of which two materials?
Metal or glass
Name some probs with suspension systems.
particle agglomeration
valve clogging
damage to container
Examples of DPIs? (2)
Turbuhaler, DISKUS
When do metred valve containers NOT contain dip-tubes
When they’re meant for inverted use
Advantages of aerosol dosage forms? (8)
- Administered directly to affected area
- rapid onset
- dosage regulated
- not easily contaminated (single dose)
- drug is protected
- decreased irritation
- fewer side effects
- convenient/easy to use
Two types of NON-pressurized devices?
- Breath-activated inhalers
2. Nebulizers
Do spacers help with drug delivery to airways?
Yes.
This type of nebulizer generates aerosol in response to the patient’s inspiratory flow.
Breath-activated nebulizer
Two types of nebulizers?
- Jet nebulizers
2. Ultrasonic nebulizers
How do spacers help with drug delivery?
Trapping large particles
What is the aerosol fmlation in pressurized aerosols composed of? (2)
- Propellant
2. Product concentrate
What’s an insufflator?
Powder blower
Why does only 10-15% of drug reach airways?
most of it is lost on the
inner surface of the adapter
and oropharynx area.
4 main components of aerosol container?
Valve, actuator, diptube, contents (ingredients+propellant)
Why is the bottom of the aerosol container curved?
allow dip tube to convey ~all of the contents
Does the pressure of compressed gas propellants drop after each use?
Yes.
What are the 3 main components of pressurized aerosol devices?
- Aerosol fmlation
- container
- valve + actuator
Two types of nebulizers?
- Jet nebulizers
2. Ultrasonic nebulizers
How do vaporizers work?
Produce steam for humidification of drug.
What type of inhaler uses metered valves?
MDIs
Do we use Raoult’s Law or the Ideal Gas Law for determining the pressure of compressed gas aerosols?
Ideal Gas Law
Which propellant type is flammable?
HC
Where are nebulizers usually used?
Hospitals
If product concentrate of aerosol fmlation is an O/W emulsion, what results? (propellant is in the INTERNAL phase)
Foam
Define aerosol
Dispersion of solid OR liquid particles in a gas
Synonym for breath-activated inhalers
Dry Powder Inhaler (DPI)
Do we use Raoult’s Law or the Ideal Gas law for determining the pressure of propellants with significant vapor pressures?
Raoult’s Law
If product concentrate of aerosol fmlation is a W/O emulsion, what results? (propellant is in the EXTERNAL phase)
Sprays/Wet streams
When do metred valve containers contain dip-tubes?
When they’re meant for upright use
What causes aerosolized droplets to form in ultrasonic nebulizers?
High-freq sound waves
Disadvantages of DPIs (10)
- Dose variability due to inspiration variability
- Loss of dry powder to inhaler and oropharynx
- Gritty sensation/taste
- Humidity
- Irritation
- Not useful for acute situations
- Powder easily lost when device is tipped
- Reqs adequate inspiration force
- Few drugs available as DPI
- No sensation of powder entering lungs = pt may repeat dose unnecessarily
Optimal drug particle size for inhalation therapy? (range)
1-5 µm
6 types of aerosol dosage forms?
Inhalations Insufflators Inhalants Aerosols Nebulizers Vaporizers
How are DPIs actuated?
By twisting the bottom of the device.
4 types of propellant?
- CFCs
- HFAs
- HCs
- Compressed gases
Non-ozone depleting alternative to CFC?
HFA
What should be done after inhaling a dose from an inhaler?
hold breath for ~10 secs
Disadvantages of nebulizers? (3)
- not portable (big machine involved)
- Expensive equipment
- Long nebulization times due to lg vol req’d to deliver adequate amts of drug
Can aerosols be compounded?
No.
Which types of propellants have a significant vapor pressure?
CFCs, HFAs, and HCs
Pressurized devices are composed of what? (3)
- Aerosol fmlation
- Container
- Valve and actuator
Disadvantages of DPIs (10)
- Dose variability due to inspiration variability
- Loss of dry powder to inhaler and oropharynx
- Gritty sensation/taste
- Humidity
- Irritation
- Not useful for acute situations
- Powder easily lost when device is tipped
- Reqs adequate inspiration force
- Few drugs available as DPI
- No sensation of powder entering lungs = pt may repeat dose unnecessarily