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Membrane Chromatography (membrane + chromatography)
Selected AbstractsEvolutionary combinatorial chemistry, a novel tool for SAR studies on peptide transport across the blood,brain barrier.JOURNAL OF PEPTIDE SCIENCE, Issue 12 2005Part 2. Abstract The use of high-throughput methods in drug discovery allows the generation and testing of a large number of compounds, but at the price of providing redundant information. Evolutionary combinatorial chemistry combines the selection and synthesis of biologically active compounds with artificial intelligence optimization methods, such as genetic algorithms (GA). Drug candidates for the treatment of central nervous system (CNS) disorders must overcome the blood,brain barrier (BBB). This paper reports a new genetic algorithm that searches for the optimal physicochemical properties for peptide transport across the blood,brain barrier. A first generation of peptides has been generated and synthesized. Due to the high content of N -methyl amino acids present in most of these peptides, their syntheses were especially challenging due to over-incorporations, deletions and DKP formations. Distinct fragmentation patterns during peptide cleavage have been identified. The first generation of peptides has been studied by evaluation techniques such as immobilized artificial membrane chromatography (IAMC), a cell-based assay, log Poctanol/water calculations, etc. Finally, a second generation has been proposed. Copyright © 2005 European Peptide Society and John Wiley & Sons, Ltd. [source] Preparation and characterization of phosphatidylcholine-coated zirconia,magnesia stationary phase for artificial membrane chromatographyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 19 2010Weinong Zhang Abstract Immobilized artificial membrane chromatography stationary phase was prepared by coating soybean phosphatidylcholine (PC) on zirconia,magnesia micro-particles. The stability and chromatographic properties were investigated and compared with the PC-coated silica chromatography stationary phase prepared by the same method. PC-coated zirconia,magnesia chromatography stationary phase was more stable than the silica especially on resisting organic solvents. Hydrophobic action was the main factor for the retention of analyte on the new artificial membrane chromatography stationary phase, and electrostatic interaction had some contribution to retention. In addition, the special interaction between analyte and matrix affected retention greatly. Basic solutes were appropriate to be analyzed on PC-coated zirconia,magnesia stationary phase and acidic solutes were appropriate to be done on the silica one. Hence, the two different matrices artificial membrane stationary phases were perfectly complementary. [source] Selective precipitation-assisted recovery of immunoglobulins from bovine serum using controlled-fouling crossflow membrane microfiltrationBIOTECHNOLOGY & BIOENGINEERING, Issue 5 2008Adith Venkiteshwaran Abstract Efficient and economic recovery of immunoglobulins (Igs) from complex biological fluids such as serum, cell culture supernatant or fermentation cell lysate or supernatant, represents a substantial challenge in biotechnology. Methods such as protein A affinity chromatography and anion exchange chromatography are limited by cost and selectivity, respectively, while membrane chromatography is limited by low adsorptive area, flow distribution problems and scale-up difficulties. By combining the traditional salt-assisted precipitation process for selective removal of Igs from serum followed by constant-permeate flux membrane microfiltration for low fouling, we demonstrate an exciting new, efficient and economic hybrid method. The high selectivity of an ammonium sulfate-induced precipitation step was used to precipitate the Igs leaving the major undesirable impurity, the bovine serum albumin (BSA), in solution. Crossflow membrane microfiltration in diafiltration mode was then employed to retain the precipitate, while using axial flow rates to optimize removal of residual soluble BSA to the permeate. The selectivity between immunoglobulin G (IgG) and BSA obtained from the precipitation step was ,36, with 97% removal of the BSA with diafiltration in 5 diavolumes with resulting purity of the IgG of ,93% after the membrane microfiltration step. Complete resolubilization of the IgG was obtained without any aggregation at the concentrations of ammonium sulfate employed in this work. Further, membrane pore size and axial Reynolds number (recirculation rate) were shown to be important for minimizing fouling and loss of protein precipitate. Biotechnol. Bioeng. © 2008 Wiley Periodicals, Inc. [source] Viral clearance using disposable systems in monoclonal antibody commercial downstream processingBIOTECHNOLOGY & BIOENGINEERING, Issue 3 2008Joe X. Zhou Abstract Once highly selective protein A affinity is chosen for robust mAb downstream processing, the major role of polishing steps is to remove product related impurities, trace amounts of host cell proteins, DNA/RNA, and potential viral contaminants. Disposable systems can act as powerful options either to replace or in addition to polishing column chromatography to ensure product purity and excellent viral clearance power for patients' safety. In this presentation, the implementation of three disposable systems such as depth filtration, membrane chromatography, and nanometer filtration technology in a commercial process are introduced. The data set of viral clearance with these systems is presented. Application advantages and disadvantages including cost analysis are further discussed. Biotechnol. Bioeng. 2008;100: 488,496. © 2008 Wiley Periodicals, Inc. [source] | ||||||||||