ABSTRACT
INTRODUCTION Ion exchange, as an ion removal technique, has historically played a very important part in the production of pharmaceutical grades of water.While the use of reverse osmosis as a primary ion removal technique has increased dramatically over the last 20 years, certain applications still employ the use of ion exchange. Water softening, a pretreatment technique to reverse osmosis (see chap. 3), or applications requiring softened water for direct use in product, such as many active pharmaceutical ingredient applications, continue to rely on ion exchange technology. USP Purified Water systems with high water instantaneous flow rates (200-300 gpm and greater) for batching applications may also employ ion exchange to minimize storage volume requirements. Conversely, USP PurifiedWater systems that use minimal volumes of water each day (e.g., <500 gal) may rely on rechargeable ion exchange canisters, with minimal maintenance, thus eliminating the need for extensive pretreatment, periodic flushing, and membrane cleaning for a small RO-based system. This section of chapter 4 discusses ion exchange as a primary removal technique in pharmaceutical water systems.
