Pharmaceutical Dosage Form and New Drug Delivery System 

Aerosols : The term aerosol has a specific meaning denoting a tine
dispersion of liquid or solid particles in a gas where the
particle size is less than 50 um it diameter, as in the case of
mist or Smoke.
Aerosols may be defined as the pressurised dosage form
of medicament in which the liquid or solid drug or drugs are
dissolved or suspended in gas. The gas used for this purpose
is known as propellant.