BY

T.Sivakumar

B.PHARMACY

1. DEFINITION

2. COMPONENTS OF AEROSOL SYSTEMS

3. FORMULATION OF AEROSOLS

4. MANUFACTURE OF AEROSOLS

5. METERED DOSE INHALER DESIGNS

6. DRY POWDER INHALERS

7. EVALUATION OF AEROSOLS

8. QUALITY CONTROL TESTS FOR AEROSOLS

Pharmaceutical aerosols are pressurised dosage forms that upon actuation emit a fine dispersion of liquid or solid materials containing one or more active ingredients in a gaseous or liquid medium. These are also to be called as pressurised packages.

ADVANTAGES:

1. It is easy and convenient to use.

2. It is used in the treatment of asthma or COPD.

3. It provides minimum contamination.

4. It provides maximum stability.

5. Systemic side effects are reduced.

1. Cost is high.

2. Irritation may occur upon topical administration of aerosols.

3. It leads to inhalation toxicity.

1. Propellants:

These are the materials which expel the contents of the container through the valves by applying force.

classification:

Liquefied gases:

1. Halogenated hydrocarbons

Ex: Fluorinated chlorinated

hydrocarbons

Trichloro monofluoro methane

Dichloro difluoro methane

2. Hydrocarbon :

Ex: Propane

Butane

Isobutane

Compressed gases:

1. Soluble gases:

Ex: Carbon dioxide

Nitrous oxide

2. Insoluble gases:

Ex: Nitrogen

various types of materials are used in the manufacture of aerosol

containers. The containers used in the formulation of aerosols should

With stand high pressure i.e.,140 to 180 psig and temperature of about 54.44 c.

Types of materials used:

1.Metal

2.Glass

Metal: Two types of metal containers are tin plated steel and aluminium

Glass: Two types of glass containers are plastic coated glass and uncoated glass.

3.Valves : They help in expelling the contents from the container.

Parts of valves :

Mounting cup or Ferrule

Valve body

Stem

Gasket

Spring

Dip tube

4.Actuators : These are specially designed buttons placed on the valve stem.

Types of actuators:

Spray actuators

Foam actuators

Solid stream actuators

Formulation of aerosols:

1.Product concentrate.

2.Propellants.

Manufacture of aerosols:

Procedure for the manufacturing of aerosols is carried

out in 2 stages

1.The concentrate is manufactured.

2.Then the propellants are added in the formulation.

Different apparatus used in manufaturing are

1.The pressure filling apparatus.

2.The cold filling apparatus.

3.The compressed gas filling apparatus.

Metered dose inhaler designs:

In this drug is dissolved or suspended in a liquid propellant mixture presented in a pressurized canister fitted with a metering valve.

Containers: Thin plated steel , plastic coated glass or aluminium

containers.

Propellants: Cholro fluoro carbons, hydrofluoro alkanes.

Metering valves: It permits reproducible delivery of small volumes of

product . It is used in inverted position.

Filling metered dose inhaler canisters:

1.Cold Filling.

2.Pressure Filling.

Advantages of MDIs: 1.portability. 2.Low cost. 3.Disposability.

Disadvantages of MDTs : 1.Poor inhalation. 2.Inefficient at drug delivery.

Dry powder inhalers:

In this drug is inhaled as cloud of fine particles. The drug is either preloaded in a inhalation device or into hard gelatin capsules or foil blister discs.They are propellant free and do not contain any excipient other than carrier like lactose.

Advantages:

1. It is useful for young children.

2.It delivers larger drug doses than MDIs.

Disavantages:

1.Liberation of powders from the device.

2.Less efficient.

1.Unit dose. • Spinhaler.• Rotahaler.

2.Multi dose.• Turbhaler.• Dischaler.

Spinhaler:The capsule is placed in a loose-fitting rotar is pierced through 2 needles.Inhaled air flow through the device causes rotation of rotar resulting in the powder being dispersed to the capsule walls and out through the perforations into the air.

Rotahaler:The capsule is inserted into an

orifice at rear of the device and when the two sections are rotated a fin on the inhaler barrel pulls the two halves of the capsule spins,dispersing its contents,which are inhaled through the mouthpiece.

Diskhaler:Here aluminium foil blisters are placed in disc.Needle will pierce the blisters as air flows the blisters causes the powder to disperse as the patient will inhales through the mouthpiece.

Turbohaler:Here drug is present in

reservoir from which it flows to disc.The disc is rotated by moving the turning grip back and forth thus drug is released which is inhaled by patient.

1. Moisture content.2. Leak test.3. Particle size determination.4. Microbial limits.

Evaluation of aerosols: 1.Flammability and combustion test. 1.Flash point test. 2.Flame projection test.

2.Physico chemical properties test. 1.Vapour pressure 2.Density. 3.Mositure content. 4. Propellant identification.

3.Perfomance test. 1. Valve discharge test. 2. pattern of spray. 3.Metered valve test. 4.Determination of particle size.

4. Biological test.

Quality control tests for aerosols:

1.Container.

2.Propellants.

3.Valves, Actuators and Dip tubes.

4.Weight checking of the container.

5.Test for leakage.

6.Spray test.

Applications:

1.Aerosols are used for oral or topical administration.

2.They exhibit systemic effect.

3.These preparations are easy to carry.

4.They are uniformly applied without touching the affected area.