Spray dried particles having specified aerodynamic characteristics are
produced by atomizing a liquid feed and contacting the liquid feed with a
drying gas, such as, for example, air or nitrogen. The humidity of the
drying gas is controlled to a value, expressed, for instance, as dew
point, which is known to produce particles having a specified tap density
or aerodynamic diameter. Particles having a volume median geometric
diameter greater than about 5 microns and a tap density less than about
0.4 g/cm.sup.3 are preferred.