1. Definition :
A suspension of small solid particles or droplets suspended in a gas or
vapor.
• Pharmaceutical aerosols are usually unstable.
• Common perception : Products that depend on the pressure of a compressed or liquefied gas to expel the contents from a container

2. Advantages of Pressurized Delivery Systems
• Portable
• Regarded as easy to use and convenient
• Remaining product is not contaminated during use
Aerosol can be filled aseptically
• Tamper- proof
• Protect unstable drugs from light, oxygen and water
• Target site need not be touched.
Provides access to hard- to-reach sites
• Provides access to systemic circulation
Expands to fill available space and provide complete surface coverage
Minimal Dripping

3. Disadvantages of Pressurized Delivery Systems
• Expensive
• Performance can deteriorate during life of product
• Flammable
Pressurized
• Sometimes prone to incorrect use

4. Uses of Pharmaceutical Aerosols
Topical
Local anesthetics (e.g.Benzocaine)
• Wound washing
• Rubiferants (e.g.Methylsalicylate)
• Spray on bandages
• Proprietary burn applications
• Antibacterials(e.g. Neomycin)
• Antifungal sprays (Miconazole)
• Anti- inflammatory steroids (e.g.Dexamethasone)
Oral and Lingual
• Antacids (e.g. Aluminum and magnesium silicate)
• Local anesthetics (e.g. Lidocaine)
• Antiseptics (e.g. Chloroseptic)
• Anti –anginals (e.g. Nitroglycerin)
Vaginal and Rectal
• Contraceptive Foams (e.g. Nonoxyenol-9)
• Local anesthetics (e.g. Pramoxine)
• Anti –inflammatory steroids (e.g.Hydrocortisone)

5. Nasal
• Decongestants (e.g. Phenylephrine)
• Anti -inflammatory steroids (e.g.Beclomethasone)
• Antiallergics (e.g. Cromolyn sodium)
• Moisturizers (e.g. Normal saline)
Ocular
• Contact lens cleaning solutions (not applied directly to eye)
Respiratory
• Bronchodilators (e.g. Albuterol)
• Anti -inflammatory steroids (e.g. Beclomethasone)
• Antivirals (e.g. Ribavirin)
• Smoking cessation (e.g. Nicotine)
Migraine (e.g. Ergotamine tartrate)

6. HYDROCARBON Propellants
Advantages
• Inexpensive
• Minimal ozone depletion
• Negligible “greenhouse effect”
• Excellent solvents
Disadvantages
• Flammable
• Aftertaste
• Unknown toxicity following inhalation
• Low liquid density

7. CHLOROFLUORCARBONS
(Used only in inhalation aerosols)
Advantages
• Low inhalation toxicity
• High chemical stability
• High purity
• CFC-11 is a good solvent
Disadvantages
• Destructive to atmospheric Ozone
• Contribute to “greenhouse effect”
• High cost

8. HYDROFLUOROALKANES
Advantages
• Low inhalation toxicity
• High chemical stability
• High purity
• Not ozone depleting
Disadvantages
• Poor solvents
• Minor “greenhouse effect”
• High cost
Examples:
1,1,1,2,3,3,3 – Heptafluoropropane (HFA-227)
1,1,1,2 – Tetrafluoroethane (HFA-134a)

9. Advantages
• Low inhalation toxicity
• High chemical stability
• High purity
• Inexpensive
• No environmental problems
Disadvantages
• Require use of a nonvolatile co-solvent
• Produce course droplet sprays
• Pressure falls during use

10. Packaging Components
Containers
Plastic Coated Glass
• Allows level of contents to be seen
• Compatible with most formulations
• Plastic coating absorbs "neckshock" during crimping and provides barrier to broken glass
• Poor aesthetic finish / difficult to label / heavy
• Used for inhalation aerosols containing dissolved drug
Aluminum
• Lightweight and seamless
• Can be screen printed, therefore visually appealing
• Easy to fill and crimp
• Incompatible with some propellants and solvents
– Can be anodized or epoxy coated
• Opaque
• Used for inhalation and topical aerosols

11. Three Piece Tinplate
• Corrosion inhibitors typically included in formulation
– Not suitable for all products
• Incompatible with some propellants and solvents
• Visible seams make them less cosmetic appealing
• Can be pressurized from the base with compressed gasses
Polyethyleneterephthalate (PET)
• Plastic containers under development
VALVES
Continuous (used for most topical aerosols)
• Product is released as long as pressure is maintained on the actuator.
Metered (Used for all inhalation, & some topical aerosols)
• A finite Volume of product is released when the actuator is pressed. No more
product is released unless the actuator is returned to its rest position and repressed
– ml for inhalation aerosols
– up to 5 ml for topical aerosols

13. Dip-tubes and Canister Orientation
• Diptubes are essential when the product is sprayed “valve up”
• Diptubes are never used when a product is only sprayed “valve down”
– Difficult to homogeneously disperse product inside a dip-tube
• Canister orientation should be described as “valve-up” or “valve- down”, not “upright” or “up-side-down”
Multi Spray-Orientation Canisters
• Valve bodies with filling holes and a dip- tube (Vapor Tap valves)
• “Bag in can” pressurized formulations
Actuators, Adapters & Dust Caps
• Dust caps keep the actuator clean
• Allow the valve stem to be easily depressed to release product
• Direct the aerosol to where it is required
• Partially control the physical form of the aerosol output

15. Quality Control Tests on Manufactured Pressurized Formulations
Standard Pharmaceutical Tests
– Identity and purity of drug
– Drug concentration and product fill weight
– Stability
• Integrity test
– no bubbles released under water at 55oC
• Propellant leakage rate test
• Product delivery rate (continuous valves only).
• Flame projection test (continuous valve only)
• Specific tests for inhalation aerosols