API Assay Limit

Why always for API is given Assay limit stringent ?
Like 98-102 or 99-101 …etc

Assay means the strength of the API. It should always be above 99%. Which Will be used for manufacturing of drug product. If the assay is lower, that means it contains impurities like inorganic salts drug profile impurities at higher level. It should be used for formulation.

But some compounds NLT 95 % also have limit

Compounds means APIs? For intermediate stage that limit can be acceptable not for API.