FIGURE 2. Mean percentage deposition of radiolabel, labeled albuterol, and unlabeled albuterol for aerosols with MMADs of 1.5 µm (A), 3 µm (B), and 6 µm (C), collected on the 9 stages of an Andersen cascade impactor operated at flow rate of 28.3 L/min. Effective cutoff diameters (e.c.d.) for the 8 impactor stages and backup filter are shown. Data are of 3 experiments, and error bars indicate SD of each value.