A LOW-LOSS CASCADE IMPACTOR WITH STAGE COLLECTION CUPS - CALIBRATION AND PHARMACEUTICAL INHALER APPLICATIONS

A new cascade impactor design having low interstage losses is describe d. A novel feature is the use of external stage collection cups, to si mplify applications requiring chemical determination of the mass colle cted on each stage. The design has been executed in versions to operat e at two flow rates: 30 and 60 L/min. Calibration data are presented f or these flow rates, and, in addition, for the latter version at 90 L/ min. Size results using the new impactor on a typical pharmaceutical i nhalation product are shown to be equivalent to those obtained using a current cascade impactor. An example is presented to indicate the uti lity of gathering size data at more than one how rate.