Manufacturing & Analytical Characterization
Adam Eason, MSc (he/him/his)
Senior Study Director
Jordi Labs
Description: Impurities in an API can significantly affect stability, efficacy, and patient safety. For example, hundreds of lots of Angiotensin II Receptor drugs were previously recalled due to the presence of high potency mutagenic impurities (nitrosamines), which resulted from a manufacturing process change. Analysis of mutagenic impurities is challenging due to their significant toxicity (i.e. very low detection limits are required for quantitative methods (parts per billion)). This also places a much higher burden on the analytical screening methods required to identify unexpected or unknown mutagenic impurities in pharmaceutical products as screening at low levels requires high instrument sensitivity and low background noise. In addition, limitations on the commercial availability of impurity standards can require alternative quantitation strategies (i.e. relative quantitation versus a surrogate standard) to be performed. Due to known response factor variation, relative quantitation has the potential to adversely affect quantitative accuracy.
Characterization of mutagenic impurities through the lens of the synthesis of amino-drug intermediates prepared via the reduction of aromatic nitro groups to the corresponding amines (i.e. nitroso and hydroxyamine impurities) will be discussed. Characterization of the amino-drug intermediates was performed using Quadrupole Time of Flight Gas and Liquid Chromatography Mass Spectrometry (QTOF-GCMS and QTOF-LCMS) to identify potential mutagenic impurities. This process was facilitated using differential analysis software to identify low level impurities. Further structural elucidation of the impurities was performed through preparative fraction collection (i.e. impurity isolation) and NMR/FTIR (i.e. characterization). Toxicological review of the resulting structures was used to asses potential safety concerns. In order to investigate quantitation strategies for the aforementioned impurities, a comparison of the response factors for structural analogs containing nitroso, hydroxyamine, amino and nitro groups was performed. Quantitative methods with improved accuracy for the nitrosamine impurities were developed and validated using triple quadrupole liquid chromatography mass spectrometry (QQQ-LCMS).