I want to find out how common is the analyses of comosite samples for impurity/degaradation of a drug prodcut by HPLC. For e.g., if one tablet does not give adequate material to detect/quantify impurity/degradation (lack of mthod sensitivity) then we have the option to use pooled samples. However, we do not know exactly the impurity level in a single tablet. This (not enough material in a single unit) may be the case for other units of prodcuts as well such as dermotology patches. In this scinario, what are the assumptions and how one jsutify pooling samples. Thank you in advance for your response.