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Aerosols are what type of dispersions?
Fine and Colloidal
Can aersols be compounded?
No. Too complex, we just distrubute them.
Definition of Aerosols?
Dispersions of pressurized liquid and/or solid drugs in a gaseous medium (propellant).
What can the contents of an aerosol?
Aerosols have the differnt formulation, stability, and efficacy considerations as other dosage forms?
False. Same considerations.
What is the difference between aerosols and other dosage forms?
Dependence upon the performance of container, valve and propellant for physical delivery of medication
What does the physical form of contents depend on?
- Type of valve employed
- Intended use
Contents in aerosols may be delivered as:
- A fine mist
- a coarse, wet or dry space
- a steady stream
- stable or fast breaking foam
What are the various types of aerosols?
- Aerosols for dermatologic therapy
- Aerosols for inhalation therapy
- Metered Dose Inhalers
- Vaginal and rectal
What are aerosols for dermatologic therapy?
- Particle size is coarser and less critical for efficacy
- Medication presented as powder, wet spray, stream of liquid (local anesthetic), gel or ointment-like products
What are aerosols for inhalation therapy (MDIs)?
Particles in form of fine liquid mist or finely divided solid
What size of particles reach the alveolar ducts and alveoli?
Particles less than 2 micrometers
What size of particles reach the bronchioles?
Particles between 5-10 micrometers
What size of drug is deposited on the trachea and bronchi?
Particles between 20-40 micrometers
How is the amount of drug regulated in a MDI?
Amount of drug discharged is regulated by an axiliary dual valve chamber that has specific capsity or dimension (dose size).
What are MDIs used for?
Largely used in inhalation therapy (potent medication).
How does a MDI work?
- Depression of actuator valve causes evacuation of champer and delivery of its contents to the atmosphere while the other valve seals from the contents of the container
- Upon release of actuator, the champer is refilled for next dose
Vaginal and rectal aerosols are sold in the form of?
Foams and creams
Translingual aerosols are?
Formulation of nitroglycerin for angina attacks
What are space aerosols?
- Also called sprays
- Aerosols used to provide airborne mist
- Particles are usually about 50 micrometers to allow dispersed droplets to remain airborne for a long time
What are surface aerosols?
Carry the active ingredient to a surface
What are some examples of surface aerosols
- Dermatologic products
- shaving creams
- dessert toppings
- food spreads
What are some advantages of aerosols?
- No contamination of contents
- No effect on drug by atmospheric oxygen, moisture and light
- Maintenance of sterility
- Drug delivered in a "clean" brocess (no wash-up before or after use)
- Good control of site of action: particle size
- Metered valves used in some containers allow exact dosage every time
- Uniform application of topical medications without touching affected area
- Providing cooling, refreshing effect locally (skin) due to rapid volatilization of propellants
What are the two features of an aerosol?
- Product concentrate
What does the product concentrate of aerosols consist of?
- Active ingredients
What can the propellant be made of?
- Liquified gases (CFCs)
- Non-liquefied compressed gases
Liquefied gases are?
Liquefied gasesFluorinated hydrocarbons (CFCs, chlorofluorcarbons)
What do CFC do?
- Reduce ozone in atmosphere and increase ultrviolet radiation reaching earth
- They are gases at room temperature and liquids when compressed or cooled below boiling point
- Frequently serve a dual role as propellant and solvent or vehicle
How long have CFCs been prohibited for general use?
Since 1978 but they are still allowed for pharmacetical use
What are some examples of non-liquefied compressed gases?
What are non-liquefied compressed gases used for?
Employed only as propellants
- Insoluble in concentrate
- Protection from oxidation
- Inert gas
- Slightly soluble in concentrateExpelled with product to achieve spraying or foaming
- Slightly soluble in concentrate
- Expelled with product to achieve spraying or foaming
What are the six principles of aerosols?
- 1) Product concentrate and propellant sealed in container
- 2) Equilibrium between liquefied propellant and vapor phase (in upper portion of container)
- 3) Vapor phase exerts pressure in all directions
- 4) Valve is pressed
- 5) Liquid phase is forced up through the dip tube and out of orifice of valve
- 6) After part of contents is expelled, equilibrium between liquid and gas propellant is reestablished
What are the types of aerosols technology?
- Two-phase systems
- Three-phase systems
- Compressed-Gas only systems
Which types of aerosol systems require shaking?
Only Two-phase and Three-phase systems require shaking of the container before use
What does the two-phase system consist of?
- Liquid phase: mixture of liquefied gase and product concentrate
- Vapor phase: gas propellent
What does the three-phase system consist of?
- Water-immiscible liquefied propellant, in bottom of container due to greater density
- Aqueous product concentrate
- Vapor phase water-immiscible gas propellants (replenished from the propellant liquid phase)
What does the compressed-gas only system?
Pressure of compressed gas in headspace of container forces product up the dip tube and out the valve
What are the ways of filling aerosols?
- Cold filling
- Pressure filling
What is cold filling and how does it work?
- Container is cooled to -30-to -40F
- Product concentrate is cooled to -30 to -40F
- Propellant is liquefied cooled to -30 to -40F
- Cold concentrate added to cold container
- Liquefied propellant added
- Valve assembly added
When should cold filling not be used?
Cold Filling is not used for aqueous product concentrate!
What is pressure filling?
- Product concentrate added to container
- Valve assembly added
- Evacuation of air by vacuum pump
- Liquefied gas is added under pressure
What type of aerosol filling method is most commonly used? Why?
Pressure filling, there is less moisture and contamination and less propellant is lost in process than cold filling
Aerosols are tested for?
- Leaks and weak points
- Proper function of valve (metered valve-USP tests for drug concentration, accuracy, reproducibility of dosage)
- Spray pattern
- Particle size
- Particle distribution in spray
When applying aerosols topically what should be done?
- affected area must be cleaned first
- facial application requires spraying into palm of hand then application
When counseling the patient on the use of aerosols what should be done?
- Verbal and written instructions
- Clarification of nasal and oral respiratory administration
- Demonstration of how to hold, shake, prime, and use
What are nebulizers?
Apparatus that produces fine particles for inhalation (rubber bulb and glass bulb-like chamber)
What are vaporizers?
- Add humidity to rooms through a fine mist of steam (may carry a medication)
- Water in tank is free of bacteria and mold
- Uses a lot of energy but quiet
What does a humidifier do?
- Adds humidity to rooms through a cool mist
- Cool down a room by 1-3 C
- Equipment more expensive, uses less elecrticity, noisier, deposits minerals on furniture
What are sprays?
- generally aqueous or oleaginious solutions for topical use on skin or nasal-pharyngeal tract
- Contain no propellant, Spray containers may have meter valve
- Ex. Nasal sprays
What are inhalations?
Preparations for respiratory adminstration (nasal or oral)
Can inhalations have systemic effects?
- Yes, drugs may be applied for systemic effects after absorption from the lungs
- Gases: oxygen, halothane
Can inhalations have local action on the bronchial tree?
- Yes, fine powders or fine mists.
- Micronized powders for inhalation+ Cromolyn sodium, for severe perennial asthma
- Solution concentrate in plastic ampule: Albuterol sulfate, cromolyn sodium
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