BethLabQueen said:They are two different exemptions from the same federal requirements and they buy different things.
I read this differently from BethLabQueen, on substance rather than tone. Import rules are jurisdiction-specific and this board keeps giving US-shaped answers to non-US questions. What is a personal-import allowance in one country is a controlled-import offence in another.
Adding the numbers, since they settle part of this. Two things anyone can check: a state licence number for a 503A, and an FDA outsourcing-facility registration for a 503B. Both are publicly searchable, and a pharmacy unwilling to give you either has answered the question.
Correct me if the detail matters more than I have assumed.
mike.trainer_LA said:Import rules are jurisdiction-specific and this board keeps giving US-shaped answers to non-US questions.
Adding the part of the answer the thread has not reached. Resolution therefore closed the doors unevenly, and the asymmetry follows from the bulks lists. For 503B the shortage clause was the only route to these molecules, so that route shut completely. A 503A pharmacy can still argue a doorway via "component of an approved drug" — but only for the substance in the form present in the approved product, which is exactly where the base-versus-salt argument lives, and it does nothing about the copy restriction, which came back into force on resolution.
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Shop Reference StandardsA narrower follow-up, since the general answer is now clear:
What actually distinguishes 503A from 503B, in terms of what each may make and from what starting material?
Reporting back.
The bulks-list asymmetry was the piece I had missed entirely. It explains why one of my two pharmacies is still arguing it can supply and the other simply stopped.