Investigations on the Spatial Dust Distribution for Emission Site Localization in Containment

Dustiness and the spatial distribution of dust are major problems when working with highly active pharmaceutical ingredients. Therefore, the aim of this study was to develop a chamber setup that allows a reproducible atomization of small powder quantities and the detection of not only dustiness but also the spatial distribution of airborne dust at extremely low concentrations, to prove that an emission site may be localized with stationary sampling even in a confined space. For this purpose, the time required for evacuation of the chamber setup was determined with fuming sulfuric acid. In subsequent atomization experiments, the safe surrogate acetaminophen was used. The spatial distribution of the surrogate was detected with nine IOM samplers (Institute of Occupational Medicine) and its quantification was carried out via HPLC. A linear tendency of the quantity of aerosol formed in dependence of the sample mass was demonstrated. In addition, significant differences between individual spots of detection and thus a spatial distribution in the detection chamber was observed. These results indicated a strong convective mass transport within the chamber setup. To verify these results, the airflow used for atomization was simulated using Computational Fluid Dynamics, confirming the convective mass transport and the spatial distribution of the airborne acetaminophen dust. In summary, it was shown that an emission site may be localized based on stationary exposure data even at concentrations as low as those mandatory in the contained manufacture of HPAPI-containing pharmaceuticals.