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48 Cards in this Set
- Front
- Back
inhalation therapy
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any procedure or device by means of which a drug can be administered by inhalation to a region of the respiratory tract
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inhalations
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drugs or drug solutions administered via nasal route for local or systemic effect
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insufflatlons
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group of products which consist of finely powdered or liquid drugs that are carried into the respiratory tract by the use of special devices
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aerosols
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products packaged under pressure and the active ingredient is released upon activation of an appropriate valve system
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Advantages of inhalation therapy(6)
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1. self-medication possible
2. inhalation therapy may replace injectable products and thereby the dangers of giving drugs by injection are avoided 3. a dose can be dispensed from the container without affecting its stability and sterility 4. medication can be delivered directly to the affected area in a desired form 5. irritation during mechanical application of topical preparation is reduced 6. onset of drug response is faster in case of inhalation therapy as compared to drugs given orally |
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components of aerosol package (4)
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1. propellant
2. container 3. valve and actuator 4. product concentrate |
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propellant
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responsible for developing the proper pressure necessary to expel the contents of an aerosol when the valve is open
-serves as solvent for certain active ingredients |
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what can propellants be classified as?
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1. liquified gases
2. compressed gases |
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liquified gases (2 types)
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a. fluorinated hydrocarbons: used in most aerosols for oral and inhalation use
b. hydrocarbons: used in topical pharmaceutical aerosols |
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examples of fluorinated hydrocarbons(liquified gases)
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-trichloromonofloromethane (propellant 11)
-dichlorodifioromethane (propellant 12) -dichlorortetrafluoroethane (propellant 114) |
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examples of hydrocarbons (liquified gas)
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propane, butane and isobutant
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compressed gases examples
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nitrogen, carbondioxide, nitrous oxide
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dalton's law
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the total pressure of a system is equal to the sum of the individual or partial pressures of the various components
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raoult's law
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depression of vapor pressure of a solvent by the addition of a solute is proportional to the mole fraction of the solute molecules in the solution
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containers
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must withstand pressures as high as 140-180 psig at 103F are used for aerosol packaging
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types of containers
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1. metal
2. glass 3. synthetic resins and plastics |
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types of metal containers
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-tin-plated
-aluminum -stainless steel |
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types of glass containers
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uncoated or plastic coated glass
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aerosol valve function (3)
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1. capable of being easily opened and closed
2. dispense the product in the correct physical form 3. should deliver desired amount of product |
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two types of valves
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-metered valves: dispenses a pre-determined quantity of material
-non-metered valve |
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actuators
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attached to valve and allows for easy opening and closing of valve
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types of actuators producing different forms of product discharge
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1. spray
2. foam 3. solid stream 4. special application: designed to deliver medications to appropriate site of action- throat, nose, eye, etc |
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formulation of pharmaceutical aerosols (two parts)
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1. product concentrate
2. propellant |
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product concentrate
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consists of active ingredients and other adjuncts (solvents, antioxidents, surfactants)
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propellant
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single or blend of more propellants
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types of formulation systems
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1. solution system
2. water-based system 3. suspension or dispersion system 4. foam system |
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processes used to manufacture aerosol products
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1. cold process
2. pressure process |
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cold process
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active ingredients are chilled and weighed into a container - the cold propellant is metered into the container - crimping the valve in place seals the container
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pressure process
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-the product concentrate is placed into the container at room temperature
-valve is crimped into place -trapped air is evacuated from container by vacuum system -propellant is added through the valve using vapor pressure of propellant to force it through valve |
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selection of propellant
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-before 1978 fluorinated hydrocarbons were used
-now hydrocarbons, compressed gases, and mechanical devices and pumps |
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selection of containers
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both glass and metal containers are used
-glass is used when total pressure is less than 25 psig and less than 15% propellant in system |
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selection of valves
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selected depending on materials of construction, size of orifice and specific applications
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selection of applicators
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selected depending on specific use of aerosol product
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stability testing of aerosols (3 areas)
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1. concentrate and propellant
2. container 3. valve |
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stability of concentrate/propellant
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-vapor pressure
-pH -density -refractive index -viscosity -total weight -assay of active ingredient, color, odor |
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stability of container
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examined for signs of corrosion during storage
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stability of valve
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examined to confirm that it is functioning, dispensing the product satisfactorily and dosing immediately after use
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testing of aerosols
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1. flammability and combustibility
2. physico-chemical characteristics 3. performance |
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flammability and combustibility
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1. flash point: aerosol chilled to -25 C, then temperature raised; point when vapor ignites is flash point
2. flame projection: measures effect of aerosol formulation on extension of open flame |
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physico-chemical characteristics
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1. vapor pressure: measured with pressure gauze, etc
2. density: determined by use of hydrometer or pycnometer 3. moisture: karl fischer or gas chromatographic method used 4. identification of propellants: gas chromatography and infrared spectrophotometry used |
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performance
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1. aerosol valve discharge rate
2. spray pattern 3. dosage with metered valves 4. foam stability 5. particle size determination |
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aerosol valve discharge rate
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change in weight per time dispensed
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spray patterns
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impingemnet of spray on piece of paper that has been treated with dyd-talc mixture
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dosage with metered valves
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-reproducibility of dosage each time valve is depressed is determined by analysis of active ingredient
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foam stability
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visual evaluation by measure the required time for a given mass to penetrate the foam or by use of rotational viscometer
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particle size determination
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cascade impactor and light scatter decay methods are used for measuring particle size
-cascade impactor a stream of particles are projected through series of nozzles and glass slides at high velocity |
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biologic testing
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limited number of tests are used to evaluate efficiency of an aerosol product
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biologic tests (2)
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1. consideration of therapeutic activity
2. toxicity (should include both topical and inhalation toxicities) |