Koch Membrane Systems” SelRO nanofiltration (NF) elements are designed for pharmaceutical laboratory and production processes. The membranes provide chemical and thermal stability to satisfy the requirements of pharmaceutical processes involving high and low pH, high temperature, and organic solvents media. The membranes are acid/base stable and can be operated within a pH range of zero to 14. They enable the concentration of pharmaceutical intermediates in aqueous solutions that may also contain methanol, ethanol, acetone, acetonitrile, and other organic solvents. Membrane modules are available in tubular and spiral configurations in a variety of pilot and large-scale commercial sizes.