Edmond Biba, Mark J. Perkins, Colin J. Hastie, Vaughan S. Langford, Claire Batty, Camilla Wilkinson

Correspondence should be addressed to: Edmond Biba, Senior Principal Scientist, US Pharmacopeia, 12601 Twinbrook Parkway, Rockville, MD 20852-1790; email: exb@usp.org.

USP general chapter Residual Solvents 〈467〉 addresses the identity and permitted level of residual solvents in drug products in the market. It includes test procedures for residual solvent analysis for much of the global pharmaceutical industry. The procedures in 〈467〉 are gas chromatography with flame ionization detection techniques, with static headspace for sample introduction. The counterpart chapter, Residual Solvents—Verification of Compendial Procedures and Validation of Alternative Procedures 〈1467〉, gives general recommendations for verification of procedures of 〈467〉 when they are used for the first time for a specific product. It also gives general recommendations for validation of other possible analytical procedures (alternative procedures) than those included in 〈467〉. Alternative procedures are permitted when they are fully validated and produce comparable results to the compendial methods or procedures. (See General Notices, 6.30 Alternative and Harmonized Methods and Procedures.) In August 2021, we published the Stimuli article “High-Throughput Residual Solvent Analysis Using Selected Ion Flow Tube Mass Spectrometry (SIFT-MS)” as an alternative procedure to those used in 〈467〉. We reviewed the public comments received for the Stimuli article and decided to conduct additional laboratory work to address some of them. The additional planned laboratory work has been completed. In this Stimuli article, we respond to comments received and support our responses with the results of additional work when applicable.