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ForumsCompounding & FormulationEndotoxin testing in compounded injectables — LAL vs rFC methods

Endotoxin testing in compounded injectables — LAL vs rFC methods

LabKate Sat, Jun 6, 2026 at 12:43 AM 17 replies 423 viewsPage 1 of 4
LabKate
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Jun 6, 2026 at 12:43 AM#1

Putting this up for argument rather than for agreement. I have read it twice and I am still not certain what it supports.

The shortage clause is the answer to the second question and it is a subtraction rather than an addition. Both exemptions forbid compounding something that is essentially a copy of a commercially available approved product. A product FDA has listed as in shortage is not treated as commercially available, so listing removed the objection that otherwise blocked compounding. It never created a permission; it withdrew a prohibition, which is why it evaporated the moment the supply fact changed.

Where I think it is weakest: the population was selected and supported in ways a real cohort is not, so I would read the effect size as a ceiling rather than an expectation.

What I am after is what actually distinguishes 503A from 503B, in terms of what each may make and from what starting material. Tell me what I have not thought of.

Note on sourcing:
Figures above are from the primary publication rather than the press summary. If a number here disagrees with one you have, post yours and we will work out which of us is reading a secondary source.
50 20JenMemphis, pat_auckland, Dr.GastroMayo and 47 others
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BenResearch_OR
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Jun 6, 2026 at 12:56 AM#2
LabKate said:
The shortage clause is the answer to the second question and it is a subtraction rather than an addition.

LabKate has the substance of this right. The condition it depends on is worth stating. They are two different exemptions from the same federal requirements and they buy different things. A 503A pharmacy is regulated primarily by the state board, needs a patient-specific prescription, is exempt from CGMP, and may use a bulk substance that has a USP monograph, is a component of an approved drug, or appears on the 503A bulks list — three independent doorways. A 503B outsourcing facility registers with the FDA, is inspected on a risk basis, must comply with CGMP, may compound for office stock without a patient-specific prescription, and has one doorway to a permitted bulk substance: the 503B bulks list, or the drug shortage list.

If somebody has the primary source to hand I would rather cite it than paraphrase it.

49 19PharmD_Rodriguez, julia.endo, JessicaM_2024 and 46 others
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KevinCompounds
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Jun 6, 2026 at 1:09 AM#3
LabKate said:
The shortage clause is the answer to the second question and it is a subtraction rather than an addition.

I read this differently from LabKate, on substance rather than tone. A research-chemical supplier selling lyophilised powder labelled research use only is not compounding and is not claiming to. It is a different legal universe with no pharmacy oversight, no patient relationship and no content guarantee, and conflating the two in these threads helps nobody.

Last edited: Jun 6, 2026 at 3:09 AM
48 18MikeKY_noInsulin, Dr.RaviCardio, jennifer_SEA and 45 others
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Dr.RenalNash
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Jun 6, 2026 at 1:23 AM#4

This one has a reasonably settled answer, so here it is. 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.

47 17anders_CPH, Dr.NutriCornell, pam_stl and 44 others
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AussieAnna
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Jun 6, 2026 at 2:37 AM#5
BenResearch_OR said:
They are two different exemptions from the same federal requirements and they buy different things.

Can confirm. Same sequence, different timescale.

46 16pete_manc_UK, anna.melb_AU, mark_tokyo and 43 others
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