Aerosols are pressurized products that contain active ingredients released through a valve system. They consist of a container, propellant, concentrate, valve, and actuator. Aerosol characteristics include particle size, dose uniformity, spray properties. Common propellants are hydrocarbon gases. Valves must be inert and meter doses accurately. Extractables from components like plasticizers must be identified and minimized. Containers are typically glass, plastic or metal. Manufacturing controls the formulation, fill weight, leakage, and valve function. Aerosol testing evaluates delivery rate, pressure, leakage, spray pattern, dose uniformity and particle size.

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2. Aerosols: are products that are packaged under pressure and contain therapeutically active ingredients that are released upon activation of an appropriate valve system. The basic components of an aerosol system are the container, the propellant, the concentrate containing the active ingredient(s), The valve, and the actuator. 2 ND NOV 2010

3. Aerosol characteristics: Particle size distribution Uniformity of dose for metered valve Delivery rate Wetness and temperature of the spray Spray pattern Velocity of spray Foam density Fluid viscosity ; 2 ND NOV 2010

7. Actuators: is the fitting attached to an aerosol valve stem, which when depressed or moved, open the valve, and directs the spray containing the drug preparation to the desired area. Containers: Made of glass, plastic or metal as stainless steel, aluminum, tin. Extractable or leachable and particulates on the internal surfaces of containers should be controlled. Manufacturing process controls usually include: monitoring of proper formulation and propellant fill weight and pressure testing, leak testing, and valve function testing of the finished aerosol. 2 ND NOV 2010

8. Topical Aerosols Delivery rate and delivered amount Only perform these tests on containers fitted with continuous valves. Procedure: Select not less than 4 aerosol containers, weigh, actuate each valve for 5 seconds, weigh each container again. Calculate the average delivery rate in g per second, for each container. Calculate the total weight loss from the container. This is the delivered amount. 2 ND NOV 2010

10. Leakage Test Only perform on topical aerosols fitted with continuous valves. Select 12 aerosol containers, weigh each container, mg W 1 , allow to stand in upright position at temp. 25  C for not less than 3 days, weigh again each container, record the weight, mg as W 2 , calculate the leakage rate mg/year. 365x(24/t) (W1-w2) 2 ND NOV 2010

11. If 1 container leaks more than 5% per year, and if none of the containers leaks more than 7% per year. Determine the leakage rate of an additional 24 containers as directed. Not more than 2 of the 36 containers leak more than 5% of the net fill weight per year, and none of the 36 containers leaks more than 7% of the net fill weight per year. 2 ND NOV 2010

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17. 2 nd nov 2010 “ The Theory & Practice Of Industrial Pharmacy” by Leon Lachman, H.A.Liberman, Joseph Kanig, 3 rd Edition, Varghese Pub., page no. 613-618. Remington’s “The Science & Practice Of Pharmacy” 3 rd Edition, Volume-I, page no.1014-1015

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