Quality control tests for Pharmaceutical Aerosols

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Quality control tests for  Pharmaceutical Aerosols

8) Quality control of Pharmaceutical Aerosols 1, 2, 3, 14, 15

Quality control of pharmaceutical aerosols include the testing of Testing of Propellant, Testing of Valves, Actuators and Dip tubes, Testing of Containers, Weight checking, Leakage Test and Spray Testing/ Spray Pattern.

8.1) Testing of Propellant/s:

All quality control testing's of propellant/s are accompanied by specifications. A sample is removed from the container and vapour pressure is determined which then is compared to specifications. The density is also checked when necessary.

Other tests include -

  • Identification of two or more mixture of propellant/s by Gas chromatography.
  • For propellant purity is checked by moisture, halogen and non-volatile residue determinations.

8.2) Testing of Valves, Actuators and Dip tubes:

Both physical and chemical examinations are done. They are sampled according to the standard procedures as found in "Military Standard Mil - STD-105D".A test method was developed for metered dose pharmaceutical aerosol by Aerosol specifications committee, Industrial Pharmaceutical Technology section, Academy of Pharmaceutical Sciences with an objective of determining the magnitude of valve delivery and degree of uniformity between individual valves.

The composition of the test solution as in table:


Test solution A

% w/w

Test solution B

% w/w

Test solution C

% w/w

Iso Propyl Myristate




Dichloro Difluoro methane




Dichloro tetrafluoro ethane




Trichloro monofluoro methane




Alcohol USP




Specific Gravity (at 25 degC)




Testing procedure:

  • Take 25 valves are selected and placed on suitable containers.
  • The containers fill with specific test solution.
  • A button actuator with 0.02 inches or larger unrestricted orifice is attached to the valves.
  • The filled containers are place in a suitable atmosphere at a temperature of 25 +- 1 0C.
  • When the products reach the temperature of 25 +- 1 0C, the filled containers are actuated to full extent for 2 seconds for complete dispensing of contents in a single delivery.
  • This procedure is repeated for a total of 2 delivered from each 25 test units.

The contents delivery through valve per actuation in uL =

Individual valve product delivery weight (in mg) / Specific gravity of Test solution



If 54 uL or less

+- 15%

If 55 uL to 200 uL

+- 10%

The limits for valve acceptance:

For 50 deliveries:

  • If Four or more deliveries are outside limits, then valves are rejected.
  • If Three or more deliveries are outside limits and then another 25 valves are tested.
  • If more than 1 delivery is outside specification, the lot is rejected.
  • If Two deliveries from 1 valve are beyond limits and then another 25 valves are tested.
  • The lot is accepted if not more than 1 delivery is outside specifications.

8.3) Testing of Containers:

  • Metal containers are examined for defects in linings. Several Quality Control aspects include specifications for degree of conductivity of electric current as measure of exposed metals.
  • For Glass containers examined for Flaws.

8.4) Weight checking:

Weight checking is done by periodically adding tared to the filling lines with tared empty aerosol containers. This will check after filling with product concentrate are removed & re weighed. Same procedure is used for checking weight of Propellants. It ensures proper blend of the propellants.

8.5) Leakage Test:

Leak test is done by checking the crimping of the valve must be available to prevent defective containers. This is accomplished by measuring the crimp's dimension and ensuring that they meet specifications. Final testing of valve closure is done by passing filled containers through water bath.

8.6) Spray Testing/ Spray Pattern:

It is to clear dip tube of pure propellant & pure concentrate and to check for defects in valves & spray pattern. For metered valves, it serves to prime the valve so that it is ready for use by the consumer.

Spray pattern checking

About the Author

Naseeb Basha Shaik's picture

Working as Assistant Professor, Pharmaceutics Department at G.Pulla Reddy College of Pharmacy, Mehdipatnam, Hyderabad.

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