Aerosol , components for aerosol formulation by firstname.lastname@example.org
COMPONENTS FOR AEROSOL
Presented by- Moriyom Akhter
World University of Bangladesh
Aerosol are the products that depend on the power
of a compressed or liquefied gas to expel the
contents from the container. Aerosols are termed
also pressurized package.
Aerosol products containing therapeutically active
ingredients dissolved, suspended or emulsified in a
propellant or a mixture of solvent and propellant and
intended for topical administration, for administration into
one of the body cavities (ear, rectum and vagina) or
intended for administration orally or nasally as fine solid
particles or liquid mists through the pulmonary airways,
nasal passages or oral cavity.
Components of aerosols:
Valve and actuator
A propellant is a chemical with a vapor pressure
greater than atmospheric pressure at 40°C (105°F).
1) It is responsible for developing the vapor pressure
within the container
Expel the product when the valve is opened and in the
atomization or foam production of the product.
When the propellant is a liquefied gas or a mixture of
liquefied gases, it can also serve as the solvent or
vehicle for the product concentrate.
Compressed Gas Propellants
Gases such as nitrogen, nitrous oxide, and carbon dioxide have been used
as aerosol propellants for products dispensed as fine mists, foams, or
semisolids. Compressed gas propellants only occupy the head space
above the liquid in the can. When the aerosol valve is opened the gas
'pushes' the liquid out of the can. The amount of gas in the headspace
remains the same but it has more space, and as a result the pressure will
drop during the life of the can.
Liquefied propellants are gases that exist as liquids under pressure.
Because the aerosol is under pressure the propellant exists mainly as a
liquid, but it will also be in the head space as a gas. As the product is used
up as the valve is opened, some of the liquid propellant turns to gas and
keeps the head space full of gas.
Compressed gas propellants
Low inhalation toxicity
High chemical stability
No environmental problem
Require use of a nonvolatile
Produce course droplet sprays
Pressure falls during use
Liquefied gas propellants
It is mainly used for the preparation of topical preparation, chemically
stable, no hydrolysis, Inflammable , low toxicity.
They are lighter than water.
Chlorofluorocarbon (CFC) propellants
P-11, P-12, and P-114 are the CFCs of
choice for oral, nasal,
and inhalation aerosols.
Low inhalation toxicity
High chemical stability
CFC-11 is a good solvent
Liquefied gas propellants
Hydrochlorofluorocarbons (HCFC) and Hydrofluorocarbons (HFC)
The hydrochlorofluorocarbons (HCFC) and hydrofluorocarbons (HFC) differ
from CFCs in that they may not contain chlorine and have one or more
hydrogen atoms. P-22, 142b, and 152a are used in topical pharmaceuticals.
These three propellants have a greater miscibility with water and therefore
are more useful as solvents. They are also slightly more flammable than the
Di Methyl Ether - This is an alternative liquefied propellant, and is more
common in personal care products, and some air fresheners. DME is
significantly higher in price than hydrocarbon propellants. Classified as a
flammable gas. It is a very strong and aggressive solvent. An advantage of
DME is its solubility in and compatibility with aqueous formulas.
Disadvantage of DME is that in aqueous formulas at levels at or above 19%,
the DME will attack the can lining thus requiring a corrosion inhibitor.
Contains two essential components:
Product concentrate : contains ingredients or mixture of active
ingredients and other such as solvents, antioxidants and
Propellant : Propellant May be single or blend of various
The type of the system
selected depends on many
factors such as
Physical, chemical and
of active ingredients
Site of application
Depending on the type of aerosol system utilized, the pharmaceutical
aerosol may be dispensed as a fine mist, wet spray, quick-breaking
foam , stable foam, semisolid or solid.
Type of systems are
1. Solution system :
Consist of a solution of active ingredients in pure propellant or
a mixture of propellant and solvents.
Easy to formulate, provided that the ingredients are soluble in
Aerosol solutions have been used
To make foot preparations
Spray on protective films
Anti-inflammatory preparations and
Aerosols for oral and nasal applications
2. Suspension or Dispersion systems
Active ingredients are suspended or dispersed throughout the propellant or
propellant and solvent phase.
Anti-asthmatic drugs, steroids, and antibiotics are delivered as suspension
aerosols. When the valve is actuated, the suspension formulation is emitted
as an aerosol and the propellant rapidly vaporizes and leaves a fine
dispersion of the product concentrate.
There are some problem arise for suspension aerosols that are include
agglomeration, particle size growth, valve clogging, moisture content, and
particle size of the dispersed aerosolized particles.
To overcome these problems:
isopropyl myristate , oleic acid
Provide slippage between particles
Lubricate components parts of the valve
Surfactants: to disperse particles
3.Water based system ( Emulsion, dispersion ):
Relatively large amounts of water can be used to replace all part or part of the
non aqueous solvents used in aerosol. These products are generally referred to
as water-based aerosols and depending on the formulation are emitted as a
spray or foam.
To produce a spray the formulation must consist of a dispersion of active
ingredients and the solvents in an emulsion system in which the propellants is
In this way when the product is dispensed, the propellants vaporizes and
disperses the active ingredients into many particles. Since propellant and water
are not miscible a three phase forms (propellants phase, water phase and
vapor phase) are used. To increase the solubility of propellants in water, ethyl
alcohol can be added to the system. Ethanol has been used as a co solvent to
solubilize some of the propellant in the water.
4. Foam system:
Foams are produced when the product concentrate is dispersed
throughout the propellant and the propellant is in the internal phase; i.e.,
the emulsion behaves like o/w emulsion.
Aqueous stable foams-The techniques used in preparing an aerosol
emulsion are the same as those used for non aerosol emulsions. This is
generally used for steroid antibiotics.
Non-aqueous stable foams-Various medicinal agents can be formulated by
Quick breaking foams-These type of system is specially applicable to
medication, which can be applied to limited or to large areas without the
use of mechanical force to dispense the active ingredients. Quick
breaking foams aerosol may be formulated by ethyl alcohol, surfactant,
water and hydrocarbon propellant.
Thermal foams - These are used when the warmness is required.
5. Intranasal aerosol:
Drug delivery systems intended for the deposition of the
medication into the nasal passageways has long been used as a
most effective, means of administering drugs intended to produce
either a local action of systemic effect.
The Intranasal aerosol offers numerous disadvantage including the
delivery of a measured dose of drug , excellent depth of
penetration into the nasal passageways with minimal intervertent
penetration into lungs, reduce droplet of particle size , lower
dosage than a comparable system preparation maintenance of
sterility from dose to dose.
The modes of administering of intranasal preparations have been
limited to nasal drops, non-pressurized nasal sprays (mist),
inhalants, intranasal gel, creams, ointments.
Wherever the medicament is needed, there the
product can be delivered in the required form like
foam, spray etc.
It have rapid onset of action. It will act on targeted
area without any contamination.
In conclusion, aerosol dosage form is a dosage form
with an easy administration. It’s main advantage is it
requires lesser amount of active ingredients or