Navigating the Uncertainties of the Nitrosamine Impurity Crisis

By March 26, 2020

The nitrosamine impurity crisis continues to be on the mind of every stakeholder involved in the development and manufacturing of affected drug products. In our interactions with key opinion leaders and those in the lab having to develop and validate nitrosamine testing methods, we’ve come across a few common questions that we want to address here.


Some published methods have named specific instruments. Are these platforms required for acceptance by regulatory authorities, and does that mean these methods are inherently “validated”?

    • It is important to know that any platform that can reach regulatory limits with a method that is fit for purpose will be accepted by regulators.
    • In all cases, a company or a lab must validate any method on their own instrument to confirm it is suitable for its intended use, even if the method originated from a regulatory agency.

What technologies are appropriate for nitrosamine analysis?

    • For routine, targeted, high sensitivity quantification of known compounds to meet future proposed regulatory limits, the preferred technology will be liquid chromatography (LC) separation combined with a triple-quadrupole mass spectrometer, such as the Xevo TQ-XS.
    • High Resolution Mass Spectrometry (HRMS) is most appropriate for process development when novel unexpected impurities can be found but could be overkill for labs looking to implement these technologies for monitoring purposes.

Why LC? What happened to GC-MS for nitrosamine analysis?

    • GC (gas chromatography) has traditionally been used for impurity analysis, but is not suitable for detection of NMBA, which is non-volatile. It is also not the right technique for detecting NDMA levels in ranitidine, due to the possibility of high temperature degradation.
    • Leveraging the enhanced selectivity of good LC column chemistry is a reliable, simple starting point for method optimization and validation across all APIs and impurities. Columns such as the ACQUITY UPLC and XSelect HSS T3 provide wholesale separation of nitrosamines, while the BEH C18 AX Atlantis Premier Column is ideal for improved resolution specifically for polar compounds, such as NMBA and NDMA from ranitidine and NDBA from sartans.

Can the same LC-MS method be used for nitrosamine analysis in both API and drug product?

    • While neat solutions for both impurities and API can be used to develop an optimized method for analyzing drug substance, drug product introduces the challenge of excipients and other matrix interference. This can lead to MS signal suppression and reduced sensitivity.
    • To achieve required detection limits without significant impurity concentration steps in sample preparation, the most sensitive triple-quadrupole mass spectrometer will likely be required. LC-MS methods developed by Waters scientists serve as a viable starting point for further method optimization

Given these challenges, it is essential that an experienced partner is there to help guide research and implementation of the best solution for individual circumstances. To reach current FDA and EMA regulatory guidelines, and when analyzing raw materials, an LC-UV system like the ACQUITY Arc UHPLC with 2998 PDA detector with an ACQUITY QDa for identification and mass confirmation, is suitable. For labs looking to future proof for ultimate sensitivity, a high-end triple-quadrupole mass spectrometry platform, such as the ACQUITY UPLC I-Class System with the Xevo TQ-XS mass spectrometer, is the LC-MS platform of choice.

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Categories: Pharmaceutical