[ifinnegan]

“Actually, the drug substance is the same”

Not sure where “actually” comes from because this is what I said.

Interesting example of small molecule drug being isolated from a mold, for example.

I’d guess that is rare now. I’d wonder if it falls under BLA now?

[Phlyer]

"Drug Substance" and "Drug" are not the same in FDA usage. One is the underlying molecule, and the other is a prepared form of it, which has an approved name.

The patent owner has the approval for the named drug. Another producer can't use the name.

So, Motrin and Advil are both drug names for ibuprofen.

When the drug becomes 'generic' it often has the drug substance name, but that doesn't mean the drug substance has been prepared the same way, even aside from the other, supposedly inert components added to the drug as sold.