Could you clarify the distinction between the starting material for chemical synthesis of an API and a source material? For example, a component of a fermentation medium used in the manufacturer or biological API. In the latter case, is audit and qualification of a supplier expected?

The definition of an API Starting Material in Part 1, Section 1 of Q7A requires that it is a
significant structural component of the API. I do not believe that source materials are defined in
Q7A, but my experience has been that typically they are materials where substantial control is
exercised over the origin and properties of material in order to achieve the desired result. In some
cases, source materials are actually licensed products in their own right such as blood
derivatives. Would an audit and qualification of the supply be expected? Well yes, and the more
complex the material becomes, the more important that qualification becomes.