Validation of filter sterilisation in autoclaves

Abstract

Filter cartridges for sterilising filtration are often sterilised by autoclavation. Although this process should be fully validated, not all process parameters are always considered. In this paper, the influence of positioning and packaging on the F 0 121°C-values at the coldest spot of the filter was investigated in the Sealkleen® and Kleenpak® housings with hydrophilic and hydrophobic filters (Pall Process Filtration Ltd., Portsmouth, UK). A temperature mapping of the assembled filters was performed and it was shown that the coldest spot was located at the sterile side at the top of the filter. The vertical position with the non-sterile side down showed the highest F 0 121°C-values at the coldest spot. The use of biological indicators confirmed this finding. Different packaging methods with medical paper had no significant influence on F 0 121°C-values for the Kleenpak® filter. The hydrophilic Sealkleen® showed significantly lower F 0 121°C-values in the open filter compared to the filter closed at the sterile side, while the hydrophobic Sealkleen® showed significantly lower F 0 121°C-values for the filter in a bag compared to the open filter and the sterile side-closed filter