Automated peak tracking for comprehensive impurity profiling in orthogonal liquid chromatographic separation using mass spectrometric detection.

The presence and quantity of impurities in pharmaceutical drugs can have a significant impact on their quality and safety. With the continuous pressure for increased industry productivity, there is urgent need for a systematic and comprehensive drug impurity profiling strategy. We report here our development of the fully automated Comprehensive Orthogonal Method Evaluation Technology (COMET) system. The system includes five columns, seven orthogonal HPLC methods, and hyphenated UV-MS detections, which provides automated generic impurities screening for any drug sample. An automated MS peak tracking approach by program-based mass spectral interpretation is devised to unambiguously track impurities among all orthogonal HPLC methods. The program passes electro-spray ionization mass spectra (ESI-MS) through four sequential decision-making mass ion tests and determines molecular weights for every peak. The system reduces the time required to obtain impurity profile from weeks to days, while the automated MS peak tracking takes only minutes to interpret all MS spectral data of interest. Up-to-date, impurity contents of 56 in-development drug candidate samples have all been successfully illustrated by COMET, which contained more than 500 chemical entities. The program is able to track more than 80% of the compounds automatically with majority of the failure due to insufficient ionization for some impurities by ESI. This system is well suited for efficient drug development and ensuring the quality and safety of drug products.