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Next Generation Pharmaceutical Impactor: A New Impactor for Pharmaceutical Inhaler Testing. Part III. Extension of Archival Calibration to 15 L/min

2004; Mary Ann Liebert, Inc.; Volume: 17; Issue: 4 Linguagem: Inglês

10.1089/jam.2004.17.335

1557-9026

Virgil A. Marple, Bernard A. Olson, Kumaragovindhan Santhanakrishnan, Daryl L. Roberts, Jolyon P. Mitchell, Buffy Hudson‐Curtis,

Air Quality Monitoring and Forecasting

An extension of the archival calibration of the recently developed 30-100-L/min seven-stage impactor, the Next Generation Pharmaceutical Impactor (NGI), has been undertaken at 15 L/min. The NGI stage cut sizes are 0.98-14.1 microm aerodynamic diameter at this flow rate. This 15-L/min calibration was motivated by the desire to sample the entire aerosol produced by a nebulizer when tested in accordance with a new international standard developed by the Comite Européen de Normalisation (CEN), as well as the need to test various types of inhalers at flow rates lower than 30 L/min for pediatric applications. Measurements were undertaken with monodisperse oleic acid droplets in the range of 0.7-22 microm aerodynamic diameter following a procedure established in the original 30-100-L/min calibration study. The NGI was found to be effective for particle size separation at 15 L/min. Users should decide the most applicable configuration that meets their needs, based on the following recommendations: (1) the pre-separator should not normally be used, as its performance is significantly degraded by the influence of gravity, resulting in interference with stage 1; and (2) a filter should be inserted below the micro-orifice collector (MOC), as the size corresponding to 80% collection efficiency of the MOC becomes excessively large with decreasing flow rate, so that this component becomes ineffective as a means of collecting fine particles that penetrate beyond stage 7.