N-Nitroso Edoxaban Desmethyl Impurity CPCA Score

Dear Members,
Limit for N-NITROSO EDOXABAN DESMETHYL IMPURITY by applying CPCA approach it comes under potency category 2.

  1. Count of hydrogen atoms on each α-carbon (lowest count first) and corresponding α-Hydrogen Score : (2,2) = 1
  2. Deactivating Feature Score (N-nitroso group in a 5- or 6-membered ring): 2
  3. Activating Feature Score (aryl group bonded to α-carbon (i.e., benzylic or pseudo-benzylic substituent on N-nitroso group) = -1

Potency score = 1 + 2 - 1 = 2

Please correct me if I am wrong.


Hi, can you share the Smiles

Smile: O=NN1CCC2=C(SC(C(N[C@H]3C@@HCCC@HC3)=O)=N2)C1.O=S(C5=CC=C(C)C=C5)(O)=O

Hi Yuvrai,
for your information it has been discussed in the below link

I have the same question before sometime and Naiffer helps me (as usual!!)
overall, your calculation is right


Thanks you chrischar for discussion link.

1 Like

Hi Yuvraj,

Regarding the activating feature score for N-nitroso Edoxaban Desmethyl Impurity, do you consider the group marked in purple as a benzylic or pseudobenzylic substituent on N-nitroso group?Why?


Thanks in advance for your help.

@dherrera, kindly refer below discussion topic for details,