This document discusses aerosols, including their classification, components, manufacturing, and testing. Some key points: - Aerosols use compressed gases or liquefied gases to expel medication from containers through specialized valves. - They are classified by administration route, valve type, dispersion system, and number of phases. - Components include propellants, containers, valves, and product concentrates. Propellants provide pressure while containers hold the formulation. - Manufacturing involves either pressure or cold filling depending on the propellant. - Testing evaluates properties like flammability, vapor pressure, density, and valve performance.

1. Aerosols
Jatin Isher & Vishal
Singh (B.pharm 3rd year)

2. INTRODUCTION
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• Aerosols - A system that depends on the power
of a compressed gas or liquefied gas to expel the
contents from the container with special valve
system.
• 1942 - First aerosol
• In 1950--- Pharmaceutical aerosol intended for
topical administration
• In 1955 - Developed for the administration
into the respiratory tract

3. Advantages
• Easy and convenient application
• Can be delivered directly to the affected area
• Rapid response to the medicament
• Reduced irritation
• Dose can be delivered without contamination
• Protect unstable drugs
• Portable
Disadvantages
• Expensive
• Propellants are toxic
• Highly inflammable
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4. Classification of aerosols
According to administration route
– Inhalation aerosols
– Non-inhalation aerosols
– Topical aerosols
According to the working way of valve
– Metered dose aerosols
– Non-metered dose aerosols
According to dispersion system
–Solution aerosols
–Emulsion aerosols
–Suspension aerosols
According to the number of phases
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–Two phases aerosols
–Three phases aerosols

5. Components of Aerosols
• Propellants
• Containers
• Valves and
actuators
• Product
concentrate
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6. Responsible for developing proper pressure within
the container.
Provide driving force to expel the product from the
container.
Types of propellants
(a) Liquefied gases (b) Compressed gases
Propellants
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7. LIQUIFIED GAS
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FLUORINATED HYDROCARBONS
Almost all types of pharmaceuticals, Inhalation and
oral
Advantages
–Chemical inertness
–Lack of toxicity
–Non flammability & explosiveness
Disadvantages
–High cost
–It depletes the ozone layer
–Damage Global Warming Potential

8. HYDROCARBONS
–Can be used for water based aerosols, topical
use
Advantages
–Inexpensive
–Excellent solvents
– It does not cause ozone depletion
Disadvantages
–Flammable
–Unknown toxicity produced
e.g. propane , butane , isobutane
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9. Recently HFA propellants are used instead of CFC
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propellants.

10. COMPRESSED GASES
- Used when the aqueous phase need not be miscible
with the propellant
- Do not have chilling effect, for topical preparation
Advantages
–Inexpensive
–Non flammable
–No environmental problems
Disadvantages
–Pressure falls during use
–Produce coarse droplet spray
–Require use of non volatile co-solvent
e.g. CO2, N2O, N2
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11. Containers
• Containers must withstand pressure 140-180
psig at 130°F
Types of Containers
• Metal containers
–Tin Plated Steel (140 - 180 psig)
–Aluminum (180 psig)
–Stainless Steel (180 psig)
• Glass containers
- Uncoated glass
- Plastic coated glass
- Plastic Containers
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12. Metal Containers
Tin plated steel containers
• It consist of a sheet of steel plate, this sheet is coated
with tin by electrolytic process
• The coated sheet is cut into three desired fabricated
pieces
• The top and body attach by soldering
Recent developments in welding include
Soudronic system- copper wire as electrode
Conoweld system – two rotating electrode rings.
• Corrosion minimized,
• Decrease product and container interaction
• Saves considerable mfg time
• Better appreciation of quality control aspects
• N
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on aqueous product can be filled
• Alcohol based pharmaceuticals e.g. spray on bandages

13. Aluminum Containers
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• Many pharmaceutical aerosols are packed in
Al containers
• Light weight, less fragile, Less incompatibility
due to its seamless nature, Greater resistance
to corrosion
• Used for inhalation and topical aerosols
• Polar solvents corrosion to Al containers
• Anhydrous ethanol corrosion to Al, produces
H2 gas, this can be overcome by anodizing Al
or addition of 2-3% water
• Non polar solvents are used in Al containers

14. Stainless Steel Containers
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• Small size containers
• Strong
• Reduce corrosion problems
• Used for inhalation aerosols
• No need for internal coating
• Costly

15. 15

16. Glass Containers
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• Compatible with most formulations
• Allows for greater degree of freedom in
container design resistant to corrosion, low cost.
• 25 psig pressure can be filled or 15% propellant
conc.
• Available with or without plastic coating
• Plastic coated glass containers can be filled to a
pressure of 33 psig
• Can be safely used
• Limited to use – its brittleness and breakage

17. 17

18. Plastic Containers
• Made with acetyl resins or poly propylene
• Can withstand high pressure
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19. Valves
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Easy to open and close
Capable of delivering the content in the desired form
such as spray, foam, solid stream etc.
It can deliver a given amount of medicament
Types
• Continuous spray valves
• Metered valves

20. 20

21. CONTINUOUS SPRAY VALVES
Used for topical aerosols
Valves assembles consist of following parts
Ferrule or mounting cup - Attach valve to container
Tin plated steel, Al , Brass (glass bottles), Under side of the
valve cup is coated with single or double epoxy or vinyl resins
Valve body or housing - Made up of nylon or derlin (0.013 to
0.080 inch)
Housing may or may not contain opening called VAPORTAP
This allows escape of vaporized propellant with liquid product
Fine particle, avoids clogging, inverted position, reduce flame
extension and chilling - FCIFC
Stem - Nylon or derlin , Gasket - Buna –N and neoprene
rubbe
2
r
1

22. Spring - Stainless steel , to hold gasket in place,
Dip tube - Poly ethylene or poly propylene , i.d- 0.120 –
0.125 inch,
Capillary dip tube – 0.050 inch
High viscous – 0.195 inches
METERING VALVE
• Used for all inhalations and some topical aerosols.
• Applicable to potent medication.
• It has defined volume of reservoir.
• It can be deliver desired volume of medicament by
de2
p
2
ressing actuator.

23. ACTUATORS
• It is a specially designed button which is fitted to the
valve.
• It delivers the product in a desired form.
• It discharges the product as spray, foam, solid stream.
Spray actuators
• It can be used for topical preparation, such as
antiseptics, local anesthetics and foot preparation
• It allows the stream of product concentrate and
propellant to pass through various openings and
dispense as spray
• The product is dispensed as a stream rather than
as a spray by the actuator when the propellant
conc. is low (50%or less)
• M
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echanical break up actuators

24. FOAM ACTUATORS
• It consist of large orifice
• Ranges from 0.070—0.0125inch
SOLID STREAM ACTUATORS
• These actuators are required for semi solid products
such as ointments
SPECIAL ACTUATORS
• These are used for a specific purpose
• It delivers the medicament to the appropriate site of
action such as throat, nose, dental and eyes etc.
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25. OBJECTIVES
• To minimize the number of administrations.
• To improve the drug delivery into the nasal passage
ways and respiratory air ways.
Metered Dose Inhalers
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26. Advantages of MDI
• It delivers specified amount of dose
• Small size and convenience
• Usually inexpensive
• Quick to use
•Multi dose capability more than 100 doses available
Disadvantages of MDI
• Difficult to deliver high doses
• Most products have low lung deposition
• Drug delivery highly dependent on good inhaler
tec
26 hnology

27. METERING VALVE
• It delivers only a specified quantity of product
• It is most critical component of MDI
• It crimped on to the container.
• The volume of valve ranges from 25—100µl for
inhalation and up to 5ml for topical use.
• Such valve consist of two valved chambers both
are connected to actuator button
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28. 28

29. Formulation
Consist of two essential components
Product concentrate – Active ingredient or mixture of active
ingredient, other solvents, anti oxidants, and surfactants.
Propellant - single or blend, is used to give desired vapor
pressure, solubility and particle size.
• Pharmaceutical aerosol may be dispensed as fine mist, wet
spray, quick breaking foam, stable foam, semi solid etc.
• Type of system selected depends on
• physical, chemical and pharmacological properties
of drug,
• Sit2e
9 of application

30. SOLUTION SYSTEM
• Large no of aerosol products can be formulated.
• Solution aerosols produce a fine to coarse spray.
• Two phase system consisting of Vapor and Liquid phase.
• No solvent is required, if active ingredient is soluble in propellant.
• Depending on the type of spray, propellant 12 or A-70 (very fine
particles) or mixture of propellant 12 and other propellants. If low VP
propellants are added to P-12, large particle size
• The vapor pressure of system is reduced addition of less
volatile solvents such as ethanol, propylene glycol, glycerin, ethyl
acetate.
• Propellant from 5% (for foams) to 95% (for inhalations).
General formula
Active drug -10-15%
Propellant 12/11 (50:50) to 100%
Types of Systems
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31. Inhalation aerosol
Isoproterenol Hcl – 0.25%W
Ascorbic acid – 0.1
Ethanol – 35.75
Propellant 12 – 63.9
Packed in S.S, Al container of 15 -30 ml
Hydrocarbons in Topical
Ethanol - 10-15
Water – 10-15
HC propellant A-46 – 55-70
Depending on water content the final product may be solution
or three
phase system.
• Hydrocarbon propellant A-70 (drier particles) while A-17
and A-31 tend to produce a wetter spray.
• These are useful for topical preparations.
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Plastic coated glass containers.

32. WATER BASED SYSTEM (Water based aerosols)
• Large amounts of water can be used to replace all or part of the non
aqueous solvents used in aerosols.
• Produce spray or foam.
• To produce spray formulation must consist of dispersion of active
ingredients and other solvents in emulsion system in which the
propellant is in the external phase.
• Since propellant and water are not miscible, a three phase aerosol
forms (propellant, water and vapor phases).
• Ethanol can be used as cosolvent to solubilize propellant in water.
• Low water soluble Surfactants and high solubility in nonpolar solvents
will be useful eg: glycol, glycerol and sorbitan esters of oleic, stearic,
palmitic and lauric acids (Conc. 0.5 to 2%)
• Propellant concentration varies from about 25 to 60%.
• Aquasol system (Aquasol valve) – dispensing fine mist or spray of active
ingredient dissolved in water (No chilling effect, since only active
in
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gredient and water are dispensed, propellant is in vapor state).

33. • Differences between aquasol system and three phase system
are
• Aquasol dispenses fairly dry spray, very small particles, non
flammability of the product
• Fine and dry spray with 6 parts of water with 1 part of HC
propellant, even it extinguishes fire.
• Alcohol use results in the two phase system
• In Aquasol system vapor phase of Propellant and product
enter actuator through separate ducts moving at high
velocity product and vapor mixed with voilent force results
in uniform fine spray
• Fine33
dry spray or coarse wet spray is obtained

34. SUSPENSION OR DISPERSION SYSTEM
• To overcome complications of cosolvents the disperse
system was developed which involves dispersion of active
ingredient in the propellant or mixture of propellants.
• To decrease the rate of settling of dispersed particles,
surfactants or suspending agents can be added.
• Primarily used for inhalation aerosols.
Epinephrine bitartrate (1-5 Microns) minimum solubility in
propellant
Sorbitan trioleate
P-114
P-12
Isoproterenol sulfate
Oleyl alcohol
Myristyl alcohol
P-12
P-11
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4

35. Steroid
Oleic acid
P-11
P-12 Oleic acid is dispersing agent, aids in reduction of particle
growth, valve lubricant avoids sticking.
Agglomeration results in valve clogging, inaccuracy of dosage,
damage to liner or container.
• Physical stability increased by
• Control of moisture content (300 ppm)
• Reduction of initial particle size to less than 5 µm for inhalation.
• Adjustment of density of propellant and suspensoid to equal
• Use of dispersing agents
• Use of derivatives of derivatives of drug with minimum solubility
in propellant (epinephrine)
Isopropyl myristate and mineral oil are used to reduce
agglomeration.
Surf
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actants of HLB less than 10 are useful (sorbitan monooleate,
monolaurate, trioleate, sesquioleate. (Conc. 0.01 to 1 %)

36. FOAM SYSTEMS
Emulsion aerosols consist of active ingredient, Aq. or non aq. vehicle,
surfactant,
Propellant.
Liquefied propellant is emulsified and generally in internal phase.
AQUEOUS STABLE FOAM
Active drug
Oil
o/w surfactant
Water,
HC Propellant (3 -5%)
• Hydrocarbon propellant (3 to 5% W/W or 8-10% V/Vusually).
• As the amount of propellant increases a stiffer and dryer foam is
produced.
• Lower propellant concentrations yield wetter foams.
HC and compressed gas propellants are used.
NON AQUEOUS STABLE FOAM
Glycols such as poly ethylene glycols used.
Emuls
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ifying agent is propylene glycol monostearate.

37. QUICK BREAKING FOAM
• Propellants are external phase
• Especially applicable to topical medications
Ethyl alcohol
Surfactant
Water
HC Propellant
THERMAL FOAM
Surfactant should soluble in alcohol and water.
• To produce warm foam for shaving
• Used to hair colors and dyes were unsuccessful.
INTRANASAL AEROSOLS
•To deliver measured dose of drug, lower doses compared to
systemic products
• Excellent penetration into the nasal passage way
• Decreased mucosal irritability
• Maintenance of sterility from dose to dose
adaptor
• D3
i7fference from inhalation aerosol is the design of

38. Manufacturing of Pharmaceutical Aerosols
PRESSURE FILLING
• Process carried out at room temp
• HC and FHC prop can be filled by this process
• Less propellant loss
• Product is filled in to the container
• Low pressure prop is introduced into the container through the
valve
• The container is then removed and filled high pressure prop up
to head of the container
• Then the container is removed and shake
• It is not used for inhalation aerosols
• Most preferable because some solution , emulsion , suspension ,
and other preparation which cannot be chilled.
• N
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ot used for metered dose inhaler

39. COLD FILLING
• In this method the propellants are refrigerated to a temperature at
least 5°F below their boiling points.
e.g. Propellant 12: BP (-30°F), refrigerate it to -35°F
• The chilled product and propellant filled into container, Valve
crimped and passed into a water bath.
• Used for inhalation aerosols
• Used with metered valves and non metered valves
• Should not use to fill HC propellants
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40. Testing of Pharmaceutical Aerosols
FLAMMABILITY AND COMBUSTIBILITY
• Flame projection: Extension of an open flame by spraying aerosol for
about 4 sec into the flame.
• Flash point: Tag open cup apparatus
Product is chilled (-25°F). Allowed to increase the temperature
and temperature at which vapors ignite is taken as flash point.
PHYSICOCHEMICAL CHARACTERISTICS
• Vapor pressure: pressure gauge
• Density: Hydrometer or Pycnometer
• Moisture content: Karl Fischer, GC
• I
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dentification of propellants: GC, IR

41. PERFORMANCE
• Aerosol valve discharge rate: Change in weight per time dispensed.
• Spray pattern
• Dosage with metered valves
- Reproducibility of dosage, each time valve is depressed
- Amount of medication actually received by patient.
• Net contents: Wtotal - Wcontainer
• Foam stability
- Visual inspection with time.
- Time for a given mass to penetrate the foam.
- Rotational viscometers
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42. PARTICLE SIZE DETERMINATION
- Cascade Impactor: 0.1 to 30 microns
- Light scatter decay: Tyndall beam
BIOLOGICAL CHARACTERISTICS
- Therapeutic activity
- Toxicity: Topical effects – irritating, chilling effect
Inhalation effects (even intended for topical
preparations)
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43. Thank You
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