I am conducting Content Uniformity Test (USP 905) for oral solution with Succus Liquiritae as its active substance. Its specification limit is set at 75.0 - 125.0 %. Should I set 15.0 % as L1 value as explained in USP 905? Because when I set 15.0 % as L1 value, then the specification become 85.0 - 115.0%?
Can anyone explain me how 85.0 - 115.0 % in USP 905 is obtained?
Normally, you shouldnt need to test content uniformity on solutions, especially if they are “true” solutions, unless they come in single dose recipients, which is unlikely in this kind product.
The 25 % limit that you mentioned is from its individual monograph. This kind of acceptance limits are related to the security and active dose of the drug.
On the otherside, the acceptance criteria from USP 905 is created to ensure that your product if evely mixed, so the limits are statiscal calculations based in sample size and reproducibility estimation.
Anyway, both kind of limits are only effective to make sure that you product complies with regulations. Any process should be controlled internally with limits obtained from the variation of a robust and controlled enviroment.