You have a global perspective and drug development program. You want to conduct studies in the US and an international location. You’re going to use an RLD from Big Pharma – you know, the global giants. The RLD bought in the US and Europe looks the same, even has the same marking. But are they same? FDA and European countries won’t accept that they are the same. Why?
Large multi-national companies, for tax and logistical reasons, manufacture their global products in many countries around the world. Some companies outsource their manufacturing operations. Due to local laws, customs, and equipment the formulation and/or process may differ from site to site. I once had the task to catalog the various formulae and processes for Seldane (the precursor to Allegra). We stopped counting at 29 unique combinations!
So, before you use an RLD from another country, you need to assure that it is the same. How? You have in vitro and in vivo methods. The choice depends on the dosage form. For instance, if you have an immediate release (IR) tablet, or an extended release oral dosage form, you could look at SUPAC guidance for inspiration on possible dissolution studies to show equivalence.
It would be wise to get FDA buy-in to your approach.