Determination of Epichlorohydrin in Active Pharmaceutical Ingredients by Gas Chromatography-Mass Spectrometry

During the development of new active pharmaceutical ingredients (API), the control of low level impurities plays a crucial role in the progression of a new compound. Particular attention is given to known or suspected genotoxic impurities, which, to ensure patient safety, have a maximum daily patient exposure limit of 1.5 mu g/day for long-term exposure (>12 months). In this communication, we report the development and validation of a part per million (ppm) level GC-MS method to detect epichlorohydrin (ECH) in a new API under development in Chemical Development at GlaxoSmithKline Verona, now an Aptuit Research Centre. GC separation was conducted on a DB-624 column, while MS detection was performed on a single-quad MSD in selected ion monitoring mode. After successful development, the method was validated according to our in-house validation guidelines for ppm level analysis. The method proved to be selective for ECH in drug substance. Sensitivity of the method (limit of quantitation (LOQ)) proved to be as low as 0.8 ppm (w/w) when the API samples were prepared at 45 mg/mL (free base). The precision (% RSD) of five preparations of spiked samples at the concentration of 8 ppm (target analytical level (TAL)) was 1.3, while recovery proved to be 97%, demonstrating the absence of matrix effect.