Two documents, two disciplines: purity and sterility are not the same trade
The Journal has read several hundred certificates from twenty companies. We set out what the documents actually cover, and what a reader is filling in from imagination.
Independent testing
Page 3 of 27 of this archive, newest first.
Janoshik, Medutest, PeptideMeter, VendorInvestigate: a capability audit
The absence of microbiological capability in this market is a commercial fact with a straightforward explanation, and it is worth understanding before blaming anybody for it.
PeptideMeter result on a Hangzhou orforglipron lot lands 0.7 points below the supplier’s figure
The result is unremarkable. What the report omits is not.
Independent analysis puts a SWB liraglutide lot at 95.6%, against 93.9% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.
What a diode array adds, and why the certificate never shows it
Non-chromophoric components — counter-ions, salts, some excipients — contribute mass to the vial and nothing at all to the chromatogram.
Independent analysis puts a MKM survodutide lot at 96.5%, against 95.5% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.
Sending the same vial twice, under two names
Two years ago we ran an anonymised version of this comparison and promised a named one. This is it, with every method printed in full.
Independent analysis puts a QST orforglipron lot at 96.6%, against 94.6% on the certificate
A reminder that a purity figure is the output of a method, and that methods differ.
LAL, kinetic chromogenic, recombinant factor C: three ways to the same figure
We submitted vials for endotoxin determination and report the results, the method and the laboratory, because a pyrogen figure without a method is as empty as a purity…
Low endotoxin recovery: the interference nobody looks for
The limit for a parenteral product is calculable from the dose and the body weight in two lines. Almost nobody in this trade performs the calculation.
A vial can be 99.4 per cent pure and not sterile in the same afternoon
Every certificate circulating in this market answers a question about molecules. Almost none answers a question about organisms, pyrogens, or the integrity of the seal.
Two ways to lift a peptide into a vacuum, and why the answer differs
The ionisation method determines the charge states you see, the adducts you must account for, and the modifications you might destroy in the process.
Why VendorInvestigate can tell you the mass is right and not that the sequence is
The Journal’s standing position: a mass that matches is necessary evidence of identity and nowhere near sufficient.
What orthogonal actually means, and what it does not
The most useful single addition to any purity determination is a second separation under a different pH or on a different stationary phase, and the second-most useful is a…
What PeptideMeter is able to certify about a sealed vial, and what it is not
Every certificate circulating in this market answers a question about molecules. Almost none answers a question about organisms, pyrogens, or the integrity of the seal.
PeptideMeter result on a Guangzhou orforglipron lot lands 1.7 points below the supplier’s figure
The supplier has not disputed the finding. It has not explained the gap either.
Custody, condition and the temperature nobody logged
The condition on arrival is recorded by some services and not others, and it is one of the more informative lines in a report.
Independent analysis puts a GL Biochem liraglutide lot at 98.5%, against 94.4% on the certificate
A reminder that a purity figure is the output of a method, and that methods differ.
Nought point nine eight of a dalton: the modification that hides in plain sight
What would be needed to catch each of these, and what it would cost.
Low endotoxin recovery: the interference nobody looks for
The limit for a parenteral product is calculable from the dose and the body weight in two lines. Almost nobody in this trade performs the calculation.