Simultaneous Determination of Two Potential Genotoxic Impurities in L-Malic Acid by Liquid Chromatography-Tandem Mass Spectrometry

Background: Genotoxic impurities (GTIs) are produced during the synthesis of active pharmaceutical ingredients and pharmaceutical excipients. L-malic acid, an important active pharmaceutical ingredient and excipient, is widely used in the pharmaceutical industry. However, the detection of potential GTIs in L-malic acid has not been reported. Objective: This study aims to establish a rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to determine the concentration of potential GTIs in L-malic acid, including N-nitroso-aspartic (NASP) and 2-chlorosuccinic acid (CSA). Methods: In this work, GTIs were separated by a reverse-phase Accucore C-18 column (100 mm x 2.1 mm, 2.6 mu m), with gradient elution using methanol and 0.05% ammonia. The multiple reaction monitoring (MRM) negative mode was used to detect GTIs, with transitional ion pairs of m/z from 131.6 to 88.0 for NASP, and from 150.9 to 70.9 for CSA. Results: The limit of detections (LODs) of NASP and CSA were 2 ng/mL (0.02 ppm) and 5 ng/mL (0.05 ppm), respectively. Both the limit of quantifications (LOQs) of NASP and CSA were 20 ng /mL (0.2 ppm). Good linearity of calibration curves in the concentration ranging from 10 to 500 ng/mL was obtained. The precision was less than 5%, and the intermediate precision was less than 10%. The accuracy ranged from 95.4% to 102.4%, with a relative standard deviation (RSD) of less than 5%. Also, the solution's stability and robustness were acceptable. Conclusion: Compliant with requirements from (International Council for Harmonization) ICH guidelines, this method can be used for routine analysis and stability studies for GTIs' levels in pharmaceutical quality control.

Automated summary

This study aims to establish a rapid and sensitive LC-MS/MS method for determining the concentration of potential genotoxic impurities (GTIs) in L-malic acid. The method is compliant with ICH guidelines and can be used for routine analysis and stability studies in pharmaceutical quality control.