Characterization of spray patterns of inhalation aerosols using thin-layer chromatography.

The spray pattern of an inhalation aerosol was characterized using photography and by observing the impaction pattern on a TLC plate. The aerosol plume was conical in shape, and its cross section increased with increasing distance from the actuator. Three puffs of the aerosol, at a distance of 3 cm between actuator and the TLC plate, produced a spot that had approximately the same diameter as the cross section of the aerosol plume at that distance from the actuator. The TLC technique with these parameters was selected to develop an assay characterizing the spray pattern of an inhalation aerosol because of its specificity, simplicity, and speed.