Liquid propellant suspension formation

The propellants used were some years agochloro-fluorocarbons (CFCs) (11 and 12) in various proportions (65 35 or 50 50). The manufacturing process includes the suspension formation in liquid propellant 11 in a cooled and hermetically closed mixer containing drug and lubricants. This mixture is introduced in the cans that are closed by a special powder valve, and propellant 12 was then injected through the valve. The upper part of the valve has often a special aperture through which a gaseous phase cleans the valve as well as the actuator. 

Propeller mixers are used for mixing liquids with viscosities up to 2,000 cp. They are suitable for the formation of low-viscosity emulsions, for dissolving applications and for liquid-phase chemical reactions. For suspensions, the upper limit of particle size is 0.1 to 0.5 mm, with a maximum dry residue of 10%. 

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