According to ICH Q2, the minimum specified range for the determination of an impurity is evaluated from the reporting level of an impurity to 120% of the specification. If the specification level of an impurity is below or equivalent to the reporting level, it is recommended that the linearity and range tests could be evaluated from 50% to 120% of the specification in accordance with USP General Chapter <1225>. Please refer to ICH Q3B for the definition of reporting level (i.e. reporting threshold) and the rationale of setting the acceptance criteria in the specification of the drug product.

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