Aerosols Flashcards
Aerosol
Any fine spray in the air
Consist of finely divided condensed matter in a gaseous medium
- Dispered phased may be liquid, solid or combination of both
Pharmaceutical aerosols
Pressurized dosage form via liquefied or gaseous propellants
- Contains terapeutic agents dissolved, suspended or emulsified in a propellant mixture or solvent/propellant mixture
Pharmaceutical aerosols are delivered as?
Fine mist, a coarse, wet and dry spray, a steady stream
A stable or a fast breaking foam
Advantages of aerosols
Meds are easily withdrawn from package without contamination
Protect from atmospheric degradation
Do not need to touch the skin
Physical form, particle size and dose are controlled
Space spray
Airborne mist
Particles are airborne for long time
Surface sprays or surface coating
Spray active ingredients on surfaces
Components of aerosols
Active ingredients and adjuncts
Propellantss
Propellants
A liquefied gas with a vapor pressure
Driving force of aerosols
CFC propellants - not used
Also can be solvents
Alternative of CFC propellants
Reduce the amount of ozone in the atmosphere and increase the amount of UV radiation
Replaced with HFA propellants
Two phase systems
Liquid phase
Vapor phase
Three phase system
Layer of water immiscible liquid propellants
Layer of highly aqueous product concentrate
Vapor phase
Solution aerosols
Therapeutic ingredients in pure propellants or a mix of propellants and solvents
Solvents: solubilize active ingredients or retard evaporation
Suspension systems
Substances that are insoluble in propellant or mixture or propellant and solvent
Aerosol formulations
Emulsion, semisolid and solution
Emulsion aerosols
Active ingredients in aqueous and non-aqueous vehickles, surfactants and propellants
Product emits as a stable and quick-breaking foam
Semisolid aerosols
Uses compressed gas such as N to push the contents from the package
Filling areosols
Step 1: Empty can
Step 2: Add formulation to can
Step 3: Fit valve and actuator to the container
Step 4: Add propellant and check can for leakage
Step 5: Fit actuator
Nebulizers
Convert aqueous solutions or micronized suspensions of drug into an aerosol
Allow recycling
Baffles: ensure large drops return to the container
Air jet nebulizers
High velocity airstream dispersion
Exit via venturi
Venturi effect
Fluid speed increases when the fluid is forced through a narrow or restricted area
- Increase spread = Decreased pressure
Standard unvented nebulizer
Most drug loss
air jet
Breath enhanced vented nebulizers
High output during inhalation phase
air jet
Dosimetric nebulizers
Produce an aerosol during inhalation phase
Ultrasonic nebulizers
Transducer of piezo-electric crystal to produce high frequency sound waves
Transducer
Converts high-frequency electrical energy into high-frequency mechanical vibrations
Piezo-electric crystal
Generate a voltage when pressure is applied or is subjected to stress
Limitations
Continuous aerosol generation
Much of the aerosol is lost
Air jet: Increased drug concentration
Ultrasonic: Increased temp = decreased MADD; cannot nebulize high viscosity liquids
Static mesh nebulizers
Liquid is pushed through a mesh by applying force
Vibrate the liquid and push droplets through the mess
Vibrating mesh nebulizers
Liquid is pushed through a vibrating mesh
Mess deform into the liquid side and pumps liquid through the holes
Aqueous solutions
Dilution
Contain perservatives
Unit dose, isotonic, and preservative free
Micronized suspensions
Poorly water soluble drugs
Cosolvents may be used
Nebulizer charge
Amount of med place din the mebulizer
Volume fill
Volume of the solution placed in the nebulizer
Drug depostion
Drug nebulzed and inhaled - drug exhaled
Drug nebulized and inhaled
= inhaled mass
