This two part chapter first focuses on the use of heterogeneous or immobilized catalysts and their ability to be recovered and recycled. The advantages and drawbacks of immobilized catalysts are described with an emphasis on their potential benefits and the issues that need to be taken into consideration for their implementation in the pharmaceutical industry. An overview of the various types of immobilized catalysts is presented including supported and biphasic systems.
The second section addresses the removal of residual metals from Active Pharmaceutical Ingredients (APIs) which can be a major challenge in the pharmaceutical industry since the specifications for residual metal in drug substance are typically extremely low. As a result, numerous metal removal techniques have been developed and the four main types, extraction, crystallization, precipitation, and adsorption are described here along with representative examples of their use in the pharmaceutical industry. The examples highlight the use of screening in identifying the best metal removal method and in many cases; several techniques are employed in tandem to obtain products with acceptable metal levels.
Keywords
Active Pharmaceutical Ingredient; Biphasic catalyst; Heterogeneous catalyst; Immobilized catalyst; Metal impurities; Metal removal; Organic solvent nanofiltration; Supported catalyst