ABSTRACT
The primary applications for pharmaceutical manufacturing are in solvent recovery and in the preparation of water for injection. Regulatory philosophy at the US Food and Drug Administration and elsewhere is that no solutes, other than the active drug and excipients, should be formulated with a drug. For many conventional drugs, the cost of purification is modest. Ideally, purification is done with a simple, inexpensive, single step that provides an immunologically pure product in a high yield. In fact, there is mutual exclusivity between several of these. The most common method for separation of dry particles is sieving, and a wide variety of analytical and process equipment is available. Crystallization is a powerful technique requiring time, tanks, and seed crystals. The immobilization of alkyl or aromatic groups on stable matrices makes possible the separation of drugs, and even proteins, from molecular contaminants based on the propensity of the drug for an hydrophobic ligand.
