6. LISTING OF IMPURITIES IN SPECIFICATIONS

The specification for a new drug substance should include a list of impurities .Stability studies , chemical development studies , and routine batch analyses can be used to predict those impurities likely to occur in the commercial product .The selection of impurities in the new drug substance specification should be based on the impurities found in batches manufactured by the proposed commercial process .Those individual impurities with specific acceptance criteria included in the specification for the new drug substance are referred to as “ specified impurities ” in this guideline .