Dispersing nasal sprays

Topical aerosols and nasal sprays rely on pump systems to deliver the API in the form of finely dispersed mist or as coarse spray or stream of semisolid. Because of their design, aerosol and nasal products are usually under very high pressure, and this makes it difficult to obtain suitable samples for analysis. In spite of that, a number of very specialized tests which include pressure test, minimum fill, number of discharges per container defivered dose uniformity, delivery rate, leak test, spray pattern and plume geometry test, assay, and microbial enumeration test (MET) have been devised to test the integrity of the aerosol package and the device used to defiver the dose. ... 

Energy is required for dispersion of the formulation as a spray. This is typically accomplished by forcing the formulation through the nasal actuator and its orifice. 

Spray, Suspension A liquid preparation containing solid particles dispersed in a liquid vehicle and in the form of coarse droplets or as finely divided solids to be applied locally, most usually to the nasal-pharyngeal tract, or topically to the skin. 

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