Antibody drugs with superior efficacy have been developed intensively in the last few decades.

However, since they are produced by mammalian cells such as Chinese hamster ovary, their cost is very expensive and needs to be reduced. For this issue, intensive researches have been continued for production of antibody drugs using microorganisms such as E. coli[17]. Although protein A chromatography is useful to recover antibody drugs from preparations, further chromatography is necessary to obtain the required purity for their clinical use. It is likely that production of antibody drugs by E. coli leads to a further requirement of selective removal of LPS. Considering the selectivity for LPS of the porous supports bearing lipid membranes, their application for purification of antibody drugs is interesting. Chemical stability of porous supports bearing lipid membranes The elution property of separation medium find more CBL0137 manufacturer is a key issue in liquid purification for the pharmaceutical industry. Elution from porous supports bearing lipid membranes of N-octadecylchitosan was evaluated by measuring the total organic buy SIS3 carbon content in an eluent from a column

packed with 20 mL of supports. The total organic carbon in the recovered water described in the experimental section was 400 μg L-1[10]. Even assuming that all of the organic carbons are due to eluted N-octadecylchitosan, the eluted N-octadecylchitosan

(C, 65.7%) is Bcl-2 inhibitor calculated as 3.0 × 10-5 g. This amount is 0.038% of the N-octadecylchitosan immobilized on the 20-mL supports. This stability for alkali is attributable to the stability of the amide linkage used for the immobilization of N-octadecylchitosan as well as the stability of the support material. Any substantial change was not observed in the IR spectra of the porous supports bearing lipid membranes after immersion in 0.5 M NaOH or 0.1 M HCl overnight at ambient temperature. This chemical stability, especially to 0.5 M NaOH immersion which is used as a standard depyrogenation procedure, is robust enough for a practical application in the pharmaceutical industry. Conclusions Porous supports bearing cationic lipid membranes of N-octadecylchitosan assembled in nanoscale adsorb LPS selectively from HSA solution at pH 4.3 to 8.0 with the ionic strength of 0.05 to 0.1. LPS was removed to as low as a detection limit of 0.020 ng mL-1 by a column-wise adsorption with a quantitative recovery of HSA. Since LPS includes a terminal diglucosamine which is negatively charged and highly substituted with long-chain fatty acids, LPS is adsorbed by both an ionic interaction and a hydrophobic one. In addition, the low pKa of the chitosan-based material as well as the rigid gel phase of lipid membranes leads to a relatively weak interaction between HSA and results in the selective adsorption of LPS.