Aerosols are defined as a disperse phase
system in which solid particles or liquid
droplets constitute the disperse phase and
gas in the continuous phase.
In 1942, First aerosol was developed.
In1950, Pharmaceutical aerosol for
topical administration was developed.
In 1955, Aerosol for the local activity
in the respiratory tract was developed
COMPONENTS OF AEROSOLS
The propellant is responsible for develop
pressure within an aerosol system to expel
material from the container.
TYPES OF PROPELLENT
• gases that exist
as liquids under
• liquid volume is
• occupy the head
space above the
liquid in the can.
• No increased in
They must be able to withstand pressures as
high as 140 to 180 psig (pounds per sq. inch
gauge) at 130 ° F.
• Tin-plated steel
• Stainless steel
• Uncoated glass
• Plastic coated
Easy to open and
It can deliver a given
• Used for topical
• Used for
These are specially
designed buttons which
helps in delivering the
drug in desired form.
TYPES OF ACTUATORS
• used for topical
• consist of large
• for dispensing
• deliver the
site of action
such as throat,
and eyes etc.
It consist of two essential components :
Product concentrate :
•Active ingredient or mixture of active ingredients and
other necessary agents such as solvents, anti oxidants
• Single or blend of various propellants is used.
• Blend of solvents is used to achieve desired solubility
•Since the opening of valve is smaller 0.018-0.030 inches,
limits the production and process become slow
•But with use of rotary filling machine, the production rate
Container must withstand pressure
140-180psig at 130F
• Tin plate steel
• Plastic coated
TIN PLATE STEEL CONTAINER
Tin-plated steel containers are light weight and
relatively inexpensive. For some products the tin
provides all the necessary protection.
However when required, special protective
coatings are applied to the tin sheets prior to
fabrication so that the inside of the container will be
protected from corrosion and interaction between
the tin and the formulation.
The coating usually is an oleoresin, phenolic, vinyl,
or epoxy coating. The tin plated steel containers
are used in topical aerosols.
Stainless steel is used when the container must be
chemically resistant to the product concentrate.
The main limitation of these containers is their high
glass containers are used in products
that have lower pressures and lower
percentages of propellants.
PLASTIC COATING GLASS
Glass can be used for various purposes like:
act as a means
PREPARATION OF PRODUCT
The aerosol concentrate consists of drug or
combination of drugs, solvents, antioxidants and
surfactants formulated as solution, suspension .
The aerosol concentrate is first prepared and
filled into the container.
The propellant is then filled into the container.
Therefore, part of the manufacturing operation
takes place during the filling operation measures
to ensure that both concentrate and propellant
are brought together in the proper proportion.
• Capable of delivering the content in the desired form
such as spray, foam, solid stream etc.
TYPES OF VALVES
CONTINUOUS SPRAY VALVE
Valve body or
FERRULE OR MOUNTING CUP :
• Used to attach valve to container.
• Made from Tin plated steel, Al , Brass .
• 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 and contains a opening at the
point of attachment of dip tube.
• Made from Nylon or Derlin , brass and stainless steel can
also be used.
• Made from Buna-N and neoprene rubber.
• Made from Stainless steel .
• Used to hold gasket in place.
DIP TUBE :
• Made from Poly ethylene or poly propylene.
• Inner diameter 0.120 – 0.125 inch.
• However for Capillary dip tube inner diameter is
0.050 inch and for highly viscous products it is
•Used for dispensing of
• Operates on the principle
of a chamber whose size
determines the amount of
• Approximately 50 to 150
mg ±10 % of liquid materials
can be dispensed at one
time with the use of such
These are specially designed buttons which helps
in delivering the drug in desired form i.e., spray,
wet stream, foam or solid stream .
TYPES OF ACTUATORS
• It can be used for topical preparation, such as antiseptics,
local anesthetics and spray on bandages etc.
• It allows the stream of product concentrate and propellant to
pass through various openings and dispense as spray.
FOAM ACTUATORS :
• It consist of large orifice which ranges from 0.070—0.125
SOLID STREAM ACTUATORS :
• These actuators are required for dispensing semi solid
products such as ointments .
• 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.
PHASES OF AEROSOLS
There are two phases
• Two phase
• Three phase
TWO PHASE SYSTEM/SOLUTION
Formed by using liquefied gases in the form
The two phases are:
Product concentrate is dissolved in
This solvent creates a homogenous
Co-solvents are added to enhance
the solubility of the active
a fine mist
or wet spray
1: A layer of water
immiscible liquid propellant
2: A layer of highly aqueous
3: The vapor phase.
THREE PHASE SYSTEM OR
WATER BASED SYSTEM
when the formulation
requires the presence of a
liquid phase that is not
If CFCs, HCFCs, and HFCs are used as the
propellants, they will reside on the bottom of
• since their density is greater than water.
If hydrocarbons are used as the propellants,
they will reside on the aqueous layer.
• since their density is less than water
Water Based System
Active ingredient is insoluble in
Surfactants are used (conc. 0.5-2%)
Propellant conc. 25 – 60%
Water act as base
Active ingredient is insoluble in
water and propellant
Active ingredient is dispersed in
the form of suspension
Particle size should be less than
Propellant conc. 6-8%
Consist of emulsion of propellant
+water +drug + emulsifier
If the propellant is in the internal phase , a
stable foam is discharged, if the propellant
is in the external phase, a spray or a quick-
breaking foam is discharged.
FOR NON AQUEOUS
LOW TEMP (-40F),
CARRIED OUT AT
COLD FILLING APPARATUS
Consist of an
insulated box fitted
with coiled copper
tubing to inc the
area exposed to
The insulated box
should be pre filled
with acetone or dry
ice, that functions
as a refrigerating
COLD FILLING PROCESS
to a temp
Chilled To a
Temp of 30-
THE VALVE ASSEBLY
IS INSERTED AND
CRIMPED INTO PLACE
OF INSIDE AIR OF
• It consists of a pressure burette capable of metering small volume of
liquefied gas in to aerosol container under pressure.
• Propellant is added from inlet.
• The propellant is allowed to flow with its own vapor pressure in the
container through aerosol valve.
• The trapped air escapes out from the upper valve
• Propellant stop flowing when the pressure of burette and container
• Additional propellant may be added by increasing the pressure in the
filling apparatus through the use of compressed gas or nitrogen gas
Through the opening
of valve propellant is
The trapped air in the
container is removed
before adding the
placed in the
Since the opening of valve is smaller
0.018-0.030 inches, limits the
production and process become slow.
But with the introduction of the rotary
filling machine, the production rate is
Trapped air should be removed.
Compressed gases are
present under high pressure
These cylinders are fitted
with a pressure reducing
valve and a delivery gauge
A flow indicator is also
Gas stop flowing when
pressure become equal.
Nitrous oxide and carbon
dioxide is used if more gas
Air is removed with
the help of vacuum
pump. Gas is
allowed to flow from
The concentrate is
placed in the container.
Valve is placed in the
It is the preferred method for
solutions, emulsions and suspension
No refrigeration is required, can be
carried out at room temperature.
Less propellant is lost.
Less chances of contamination.
Certain metering valves
cannot handled due to
Slower process than cold
AEROSOLS A unique aspect of pharmaceutical aerosols as
compared to other dosage forms is that the product is
actually packaged as part of the manufacturing
Most aerosols have a protective cap that fits snugly
over the valve & mounting cap.
this protect the valve against contamination with dust
The cap which is generally made up of plastic or
metal also serves a decorative function .
Expose to temp.
above 49 C (120 F)
may burst an
containers are cold
less than the usual
spray may result.
These products are
15C - 30C (59F &
Medicinal aerosols are labeled by the
manufacturer with plastic peel-away
labels or easily removed paper labels.
use & storage:
For safety, labels
must warn users
not to use or
store them near
heat or an open
regard to shaking
before use &
holding at the
Proper Administration & Use
Of Pharmaceutical Aerosols
should make every
attempt to educate
the patient about
should provide the
patient written as
well as verbal
told how to
hold it &
how to use
If the patient can not
use the inhaler it is
advisable for the
recommend to the
patient or the patient’s
physician the use of
an extender device
with the inhaler.
They can effectively
assist the delivery of
The patient should first
clean the affected area
gently & pat it dry.
Holding the canister
with the nozzle
pointing towards the
Then press down the
button to deliver
enough medication to
cover the area.
Not cover the area
with the bandage or
instructed to do so.
VAGINAL & RECTAL
The foams are
Inserter filled with
foam & placed in
the vagina through
activation of the
Vapor pressure, density, purity &
acceptability of the propellant are
determined & compared with specification
•Valve acceptance, delivery rate
•Sampling is done according to standard procedures as
found in Military Standards “MIL-STD-105D”.
•For metered dose aerosol valves ,test methods were
Aerosol Specifications Committee
Industrial Pharmaceutical Technology Section
Academy Of Pharmaceutical Sciences
•The objective of this test is to determine magnitude of valve
delivery & degree of uniformity between individual valves.
•Standard test solutions were proposed to rule out variation in
From 25 test
Repeat it for
• Examined for defects in lining.
• Q.C aspects includes degree of conductivity of electric current as
measure of exposed metals.
• Glass containers are examined for Flaws.
•Done by periodically adding to the filling line tarred empty aerosol
containers, which after filling with concentrate are removed &
• Same procedure is used for checking weight of Propellants being
•Means of checking crimping of the valve & detect the defective
containers due to leakage.
•Done by measuring the Crimp’s dimension & comparing.
•Final testing of valve closure is done by passing the filled containers
through water bath.
•Most ph aerosols are 100% spray tested.
•This serves to clear the dip tube of pure propellant and pure
•Check for defects in valves and spray pattern.