If impurities are easy to purify and remove, and unknown impurities can be controlled within 0.10%, they do not need to be evaluated.
During the later stages of process optimization, impurities in typical samples are systematically analyzed. If they exceed the identification threshold and are speculated and confirmed as PGI, a purification study is required, and limits are controlled according to ICH M7.
【PGI generated and confirmed according to the process route must be studied and limited controlled according to ICH M7】