caa a22 4500 477126812 CHVBK 20180405111652.0 cr unu---uuuuu 170330e19971201xx s 000 0 eng 10.1023/A:1012175612193 doi (NATIONALLICENCE)springer-10.1023/A:1012175612193 Variability in Size Distribution Measurements Obtained Using Multiple Andersen Mark II Cascade Impactors [Elektronische Daten] [Stephen Stein, Bernard Olson] Purpose. Andersen Mark II cascade impactors are commonly used for the testing of pharmaceutical aerosols. The reproducibility of size distribution measurements made with various Mark II impactors was assessed theoretically and experimentally. Methods. Stage cutpoints were calculated for fourteen Mark II impactors based on jet diameter measurements for each stage. The calculated cutpoints were used to predict differences in size distributions measured with various Mark II impactors. Five impactors were exposed to an atomizer-generated oleic acid test aerosol to experimentally verify predicted differences in size distribution measurements among impactors. Results. Stage cutpoints were calculated to vary by up to 0.45 micron for 'identical' stages of different Mark II impactors based on jet diameter measurements. The size distributions measured with various Mark II impactors were shown to be significantly different based on theoretical and experimental observations. For one particular experiment, the amount of material collected on Stage 6 ranged from 26.8 percent of the total sampled mass to 40.9 percent depending on which Mark II was used. Theoretical calculations predicted that the amount of material collected on Stage 6 would vary from 24.0 to 43.5 percent of the total sampled mass among impactors for this experiment. A Similarity Ratio, useful for interpreting the test results, was defined and discussed. Conclusions. Significant differences in stage cutpoints exist among Andersen Mark II impactors. These differences in stage cutpoints can result in large differences in size distribution measurements made with various Mark II impactors. By measuring jet diameters and calculating stage cutpoints, it is possible to predict the performance of a particular Mark II impactor. Plenum Publishing Corporation, 1997 Andersen cascade impactor nationallicence size distribution nationallicence metered dose inhaler (MDI) nationallicence lognormal distribution nationallicence variability nationallicence Stein Stephen 3M Pharmaceuticals, 3M Center, Building 260-4N-12, 55144-1000, St. Paul, MN aut Olson Bernard University of Minnesota Mechanical Engineering Department, Minneapolis, Minnesota aut Pharmaceutical Research Kluwer Academic Publishers-Plenum Publishers 14/12(1997-12-01), 1718-1725 0724-8741 14:12<1718 1997 14 11095 https://doi.org/10.1023/A:1012175612193 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1012175612193 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Stein Stephen 3M Pharmaceuticals, 3M Center, Building 260-4N-12, 55144-1000, St. Paul, MN aut NATIONALLICENCE 700 1- Olson Bernard University of Minnesota Mechanical Engineering Department, Minneapolis, Minnesota aut NATIONALLICENCE 773 0- Pharmaceutical Research Kluwer Academic Publishers-Plenum Publishers 14/12(1997-12-01), 1718-1725 0724-8741 14:12<1718 1997 14 11095 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer