Related substances calculation as per EP

[vishall79]

Dear All,
I am preparing a standard testing procedure of a EP monograph.
As per EP calculations, impurities peak areas are compared with dilute test solution. here the weight of test material taken is not taken into comparision. Can anybody please explain me complete calculation of Related substances in EP?
Should the weight of the test material be taken in calculation?

[krickos]

Hi

Traditionnaly the EP related substances tests are designed more as limits test rather than quantative where the diluted "standards" are compared with the sample preparation. Thats the reson why actual weight is not taken into account.