PT - JOURNAL ARTICLE AU - Doorne, Hans Van TI - Sorption of Bacterial Endotoxin and Retention of Bacteria by Positively Charged Membrane Filters DP - 1993 Sep 01 TA - PDA Journal of Pharmaceutical Science and Technology PG - 192--198 VI - 47 IP - 5 4099 - http://journal.pda.org/content/47/5/192.short 4100 - http://journal.pda.org/content/47/5/192.full SO - PDA J Pharm Sci Technol1993 Sep 01; 47 AB - Positively charged membrane filters (Pall, Posidyne®) were studied for their ability to retain both bacterial endotoxins and bacteria. Filters (0.2 μm pore size) were challenged with high (up to 5*105 EU) levels of bacterial endotoxin. When the endotoxin was dispersed in water, a more than 10.000 fold reduction of the endotoxin was obtained, whereas the reduction was only a factor 20 when Ringer’s solution was used to disperse the endotoxin. Retention of bacteria was dependent on the type of organism, the pore size of the filter and the suspending liquid. Although filters with pore sizes >0.2 μm were not suitable to be used as a final filter in an aseptic production process, a very reduction in the number of bacteria could be obtained. Possible applications for these filters in the production of sterile pharmaceuticals are discussed.