Janoshik, Medutest, PeptideMeter, VendorInvestigate: a capability audit
We asked all four services what they can determine, on what timescale, at what price, and under what accreditation. The answers are printed in full.
Analytics
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PeptideMeter result on a Hangzhou orforglipron lot lands 0.7 points above the supplier’s stated figure
The result is unremarkable. What the report states alongside it 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.
Deamidation is the commonest degradation route and the hardest to see
An isoaspartate rearrangement changes the molecule and not the mass. A method that confirms identity by molecular weight alone will report it as the parent compound.
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.
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…
PeptideMeter result on a Suzhou liraglutide lot lands 4.0 points above the supplier’s stated figure
The result is unremarkable. What the report states alongside it is not.
Janoshik result on a Zhuhai tirzepatide lot lands 2.5 points above the supplier’s stated figure
A reminder that a purity figure is the output of a method, and that methods differ.
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.
Independent analysis puts a FGP exenatide lot at 95.8%, against 93.2% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
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.
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…
PeptideMeter result on a Guangzhou orforglipron lot lands 1.7 points above the supplier’s stated figure
The supplier confirmed the determination and supplied the method behind its own figure inside a week.
The retest date and the expiry date are not the same document
A retest date says that material should be re-examined before use. An expiry date says it should not be used. The trade uses the second word for the first concept.
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.
The degradation product that elutes underneath the parent peak
Deamidation, oxidation, aggregation and hydrolysis account for nearly all of what happens to a peptide over time. Each has a characteristic residue, a characteristic…
Independent analysis puts a BCH mazdutide lot at 96.0%, against 93.7% on the certificate
A reminder that a purity figure is the output of a method, and that methods differ.
Independent analysis puts a MKM liraglutide lot at 99.0%, against 97.4% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.