Analytical tech transfer requirement

Dear All,

If API is official in Pharmacopoiea (B.P AND EP) and manufacturer has COS (Certificate of suitability) in that specification has Related substance test and residual solvent test other than pharmacopoieal test, in such case analytical tech transfer is necessary for RS and Residual solvent or it is not required as API is official in Pharmacopoiea . What is the EU requirement ?

Definetely it is required to transfer the method,because when it was validated with the inclusion of impurities(which is related to process) due to the process we have to tranfer the method to the manufacturing site.