Headspace Sampling of Residual Solvents per USP 467

During the synthesis of some pharmaceuticals it is sometimes necessary to use solvents in order to increase the yield or purity of the product. After the pharmaceutical is produced, the solvent(s) are removed to the greatest extent possible. The products are then tested for any residual solvents in order to limit patient exposure. Residual solvents are separated into classes according to the risk to patient health. Class 1 solvents are to be avoided at all costs as they are known to be human carcinogens or have adverse effects on the environment. Class 2 solvents have less severe toxicities but should be avoided because of the potential of adverse effects. Finally, Class 3 solvents have low toxicity and can be used when needed as long as they are below established limits. Pharmaceutical manufacturers are required to test for residual solvents in order to ensure that any residual solvents in the product are below established exposure limits. United States Pharmacopeia (USP) general chapter <467> describes a static headspace gas chromatography procedure for the determination of residual solvents. This application will demonstrate the USP <467> procedure using an autosampler configured with a gas tight syringe for static headspace sampling.