HPLC Separation of Diazepam Conformers Coupled with Off‐Line NMR Experiment

Intelligent Multidimensional Purity Analysis and Confirmation Tool for Multiple Attribute Analysis

Chiral active pharmaceutical ingredients (APIs) are known to bind to chiral biological targets with better on-target specificity than achiral ones. However, the methods of synthesizing such APIs stereoselectively require the exhaustive optimization of multiple quality attributes of an asymmetric synthesis, wherein all critical quality attributes (for example, chemical and stereochemical purity of the API) are to be optimized in parallel and ideally from the beginning of the drug development program. A multidimensional liquid chromatographic tool capable of simultaneously measuring multiple quality attributes from a single analytical injection is reported. The tool is designed for the recirculation of chromatographic eluent bearing an analyte of interest through one or more stationary phases using a new and uniquely designed heart-cut valve. The iterative measurement of a target analyte from just one single injection will help scientists identify whether an unknown impurity is formed during reaction or during analysis. This chromatographic tool is particularly useful in the discovery of on-analysis artifacts, which is a resource-intensive exercise involving the identification, synthesis, and injection of impurity standards, all of which delay the drug development program.