Q7A makes a distinction between further processing and blending. In the case of further
processing you are continuing to process in house, and you are going to do subsequent testing.
One example of combining fractions from several batches for further processing is charging
multiple batches of intermediate into the next step of the process.
Q7A addresses blending from the point of view that you are selling the product, your intermediate
or API. If you take pieces of more than one thing and put them together to sell them, what do you
need to do? You need to test those pieces before you put them together, you need to ensure that
you are not blending out of specification material, you need to do stability studies on final blended
material if there’s any reason to believe that blending could affect the stability. So there are a
number of expectations specific to blending.
We addressed blending in Q7A partly because the term has been commonly used in our industry.
At the time Q7A was being developed there was a lot of discussion within FDA about blend
uniformity, about what size sample you should take for blend uniformity, about the fact that blend
uniformity testing should be done on every batch. That is applicable to drug product only, it is not
applicable to APIs. That was why we addressed blending in Q7A to be very clear that blend
uniformity testing was not applicable to APIs.
