🤷‍♂️ FAQ: How do I calculate the CPCA of my Nitrosamine Impurity?

[Yosukemino]

Visualization of categorized compounds

Visualization of Categorized Compounds by CPCA

I want to visualize categorized compounds by CPCA in EMA Q&A rev.16. [image] Category 5 [image]

Calculation of α-hydrogen score (Illustration of @David’s description)

EMA Q&A Rev. 16 EMA/409815/2020 - MAJOR UPDATE

Dear @David Thank you for your helpful and informative explanation. Of course, I remember you helped us in this community many times. And I want to illustrate your explanation to understand nitrosamines deeply. If the most-hindered side is CH2, then whether the right-hand side is CH2 or CH3 makes little difference, both sides can react and highly-reactive diazonium ions can form, hence the score of 1 - reflected in a number of potent carcinogens that match this unhindered pattern. [image] I…

About the exception of CPCA (Nitrosamides and others)

EMA Q&A Rev. 16 EMA/409815/2020 - MAJOR UPDATE

As EMA was starting to look at nitrosamides, I wrote a white paper in a hurry to indicate that these are not nitrosamines but “Nitrosamides”. I have a posting here “Nitrosamides - horse of a different color”. These products are direct acting carcinogens and should not be treated as nitrosamines. So, you can do a general Ames assay to see if they are positive. also, treat them as mutagenic impurity and use SAR. Most of them will have higher limits. Again, they are not nitrosamines. So, dont apply…