What is the definition of an aerosol?
Dispersions of pressurized liquid and/or solid drugs in a gaseous medium (propellant
What are the characteristic of aerosols?
- Contents form: liquid, powder, ointment, cream, gell foam
- They are dependent upon the performance of container, valve and propellant for physical delivery of medication
What are aerosols delivered as?
- A fine mist
- A coarse, wet or dry spray
- A steady stream
- Stable or fast-beraking foam
What are the facts about aerosols for dermatologic used?
- Particle size is coarser and less critical for efficacy
- Medication presented as powder, wet spray, stream, of liquid (local anesthetic), gel or ointment like product
What is the particle size for inhalation aerosols?
Particles in form of fine liquid mist of finely divided solid
What are the size of particle required to reach the alveolar duct, bronchioles, on traachea and bronchi?
- Alveolar duct: less than 2 mcm
- Bronchioles: 5 to 10 mcm
- On trachea and bronchi: 20 to 40 mcm
What are metered dose inhalers?
- The amount of drug discharged is regulated by an auxiliary dual valve chamber that has specific capacity or dimension (dose size)\
- Potent medication
What does a dual valve chamber do?
- Depression of actuator valve causes evacuation of chamber and delivery of its contents to the atmospher while the other valve seals from the contents of the container
- Upon release fo actuator, the chamber is refilled for next dose
What are two additional pharmaceutical uses for aerosols?
- Vaginal and rectal
What are space aerosols?
- Aerosols used o provide an airborne mist
- Larger particle usually 50mcm to allow duspersed droplets to remain airborne for a long time
What are surface aerosols?
- Carry the active ingredient to a surface
- Ex: dermatologic products, deodorants, cosmetics, perfumes, shaving creams, paint, cleaners, lubricants, dessert toppings, food spreads
What the advantages to aerosols?
- No contamination of contents
- No effect on drug by atmospheric oxygen, moisture and light
- Maintenance of sterility
- Drug is delivered in a clean process
- good control of site of action
- Metered valves used in some containers allow axact dosage every time
- Uniform application of topical medications without affeted area
- Provide cooling, refreshing effect locally due to rapid volatilization of propellant
What are liquified gases?
- Flurinated hydrocarbons or CFCs=chlorofluorcarbon
- Are gases at room temperature and liqui when compressed or cooled below boiling point
- Serve a dual role as propellant and solvent or vehicle
- Are pohibited since 1978 for general use except for pharmaceutical use because they reduce the ozone layer
What are non-liquified compressed gases?
Employed only as propellants
What are examples of non-liquified compressed gases?
- N2=nitrogen: insoluble in concentrate, odorless, tasteless, protection from oxidation, inert gas
- NO2= nitrous oxide: slightly soluble in concentrate, expeled with product to achieve spraying or foaming
- CO2= carbon dioxide: slightly soluble in concentrate, expelled with product to achieve spraying or foaming
What is the aerosol principle?
- There is an equilibrium between liquified propellant and vapor phase (in upper portion of container)
- Vapor phase exerts pressure in all directions
- When the valve is pressed the liquid phase is forced up through the dip tube and out of orifice
- Then equilibirium os reestablished
WHat is compressed-gas only systems?
Pressure of compressed gas in headspace of contaeiner forces product up the dup tube and out of valve
What type aerosol require shaking of the container before use?
Two phase and three phase system
WHat is the cold filling method not used for?
- Aqueous product concentrate
- Because the cold temperatures will freeze the product
What is the process of cold filling for aerosols?
- Container, Product concetrate, Propellant is liquified when is cooled to -30 to -40 oF
- COld concentrate added to cold container
- Liquified propellant added
- Valved assembly added
What is the most common method of preparing aerosol for pharmceutical products?
- Pressure filling
- Because there is less moisture contamination and less propellant is lost in process
What is the process of pressure filling for aerosols?
- Product concentrate added to container
- valve assembly added
- Evacuation of air by vacuum pump
- Liquified gas is added under pressure
WHat does the USP check for in aerosols?
- Leaks, weak point
- Proper function of valve (metered valve)
- Drug concetration
- Reproducibility of dosage
- Spray pattern
- Particle Size
- Particle distribution in spray
What are some counceling facts for topical aerosols?
- Affected area must be cleaned fist
- Facial application requres spraying into palm of hang then applied
Can aerosol be applied for systemic effects?
Yes after absorption form the lungs
What is the two phase system?
- Liquid Phase: mixture of liquified gases + product concentrate
- Vapor Phase: gas propellant
What is the three phase system?
- Water immiscible liquified propellant: in bottom of container due to greater density
- Aqueous product concentrate
- Vapor Phase: water immiscible gas propellant to replenish from propellant liquid phase
What are inhalations?
- Preparations for respiratory administration (nasal or oral)
- Drugs may be applied for systemic effects after absorption from the lungs
- Drugs man have local action on the bronchial trees