Challenges in Confirmatory Testing for Nitrosamines potential presence Identified from Step 1 Risk Assessment

During the Step 1 risk assessment for a drug product, a situation may arise where the product is identified as being at risk for the presence of nitrosamines. However, in some cases, the specific nitrosamine moieties cannot be determined due to a lack of information about the potential presence of nitrites or nitrosating agents in the excipients used in the product’s formulation.
In such scenarios, the conclusion of potential nitrosamine risk is driven by the absence of data rather than positive evidence. This presents a challenge for the subsequent confirmatory testing phase, as a screening method capable of detecting a broad range of nitrosamine compounds must be employed, rather than a method specifically targeting known nitrosamine impurities.

Have others encountered similar situations where the Step 1 risk assessment indicates a potential nitrosamine risk without providing clarity on the specific nitrosamine moieties of concern? If so, what approaches or strategies have been employed for the confirmatory testing phase, particularly in selecting and validating a suitable screening method? Insights and experiences related to this scenario would be valuable for discussion.


Very true…ATNC / Apparent total nitrosamine content will give clear broader picture of the overall nitrosamine impurity risk profile of the product.

ATNC (Apparent Total N-nitroso group Content) is a procedure accepted for cosmetic products:
SCCS Opinion on Nitrosamines and Secondary Amines in Cosmetic Products
I do not know if it may be accepted by Health Authorities for medicinal products; it depends from the validation of the method and its detection limit.
In any case, if you will find detectable NOCs, you should identify them and therefore develop a specific method.

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I agree on this and case by case, we have to act.

Yes, I agree with you Alexandros
Many times, observed similar situations, where insufficient relevant information or appropriate controls on the nitrite / dialkyl amines sources in API and excipients will make these kind of situation. Indeed, considering all the trivial risk carrying to alone DP pose a significant challenges.
We need to wait to see on this further to conclude from the experience’s and data.

HI @Alexandros

I can add a little more info on ATNC analysis and its use as a screening tool. For context, I work for ellutia and we produce and supply equipment that performs ATNC analysis.

This approach has both benefits and drawbacks from an analytical perspective, but we believe it can be a useful tool for screening. The System works by chemically breaking off the NO group from the nitrosamine, which is then detected by a TEA detector (chemiluminescence). This means that it will give a signal from nitrosamines regardless of their structure. There is no separation so you will get a single result for any compounds present that give a signal. The advantage of this is we don’t need standard for every nitrosamine or even know what it is. We are able to create a calibration curve using any nitrosamine standard and still detect any other. The challenge comes that nitrites and nitrates will also give a signal so there is the potential for a false positive if you are just looking for nitrosamine content. Though I guess from a risk assessment perspective a signal even if generated by nitrites may be a useful indicator for the potential for nitrosamine formation. The one thing the system wont give though is a false negative so if a result does come back very low or blank you can be confident that there is no or very low levels of a nitrosamine, nitrite or nitrate.

In the cosmetics industry a low result or blank is accepted but if a positive result is found using this technique then further testing must be carried out to identify the source of the signal.

When using the automated version of the system we can see down to 1ppb of ndma.

Hope that is helpful if you have any other questions happy to try and answer.

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