The badge is about a sample. The listing is about a product.
A badge asserts that something was tested. It does not assert what, when, on whose sample, by what method, or whether the lot on sale is the lot that was tested.
Testing Dispatch
Independent analysis puts a ERP survodutide lot at 95.6%, against 92.3% on the certificate
A reminder that a purity figure is the output of a method, and that methods differ.
Janoshik has published a purity determination of 95.6% on a 10 mg vial of survodutide supplied by ERP, against a figure of 92.3% on the certificate that accompanied the vial. The sample was submitted by the Journal in October 2024 as part of a continuing programme of arm’s-length purchasing, and the vendor was told before the order was placed that any result would be published.
The Journal purchased 14 vials from the same lot at retail and had four of them analysed separately, in order to distinguish vial-to-vial variation from method variation. Vial-to-vial agreement was within 0.4 percentage points. Method-to-method disagreement was an order of magnitude larger.
Reported figures across the set were: highest 95.6%, lowest 92.3%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 22 of them stated an integration threshold. The Journal has asked the laboratory to publish thresholds on all reports as a matter of routine.
Purity became this trade’s single figure of merit because it is the cheapest measurement to obtain and the easiest to compare. Peptide content, which determines how much drug is actually in a vial, costs several times as much and is quoted as a priced addition by most of the twenty companies in the Journal’s dossier programme rather than carried as a standard release test. Sterility and endotoxin are separate disciplines again, and are neither tested nor claimed.
"Ask for the suitability summary before you argue about the percentage," said Lorcan Feeney, analytical services director at an independent laboratory. "If the tailing factor and the replicate precision are outside limits, you are arguing about arithmetic performed on an unfit separation."ERP’s dossier has been updated with this determination and with the company’s response to it. The dossier’s ordering box records the lead times, the minimum quantities and what a buyer should ask for at the point of order.
Related coverage
Electrospray, MALDI, and the choice that shapes every spectrum after it
The two ionisation techniques in general use produce different charge distributions, different adducts and different failure modes. Certificates almost never say which was…
The named comparison we promised two years ago
The Journal submitted split samples from single lots to three assay services, under names unconnected to this publication, and published each method alongside each result.
SGN names the synthesis and fill sites behind its catalogue
Documentation practice is the only part of vendor quality a buyer can assess before purchase.
Independent analysis puts a GL Biochem semaglutide lot at 97.8%, against 94.6% on the certificate
A reminder that a purity figure is the output of a method, and that methods differ.
Electrospray, MALDI, and the choice that shapes every spectrum after it
A brief and unromantic tour of the interface between a liquid sample and a vacuum.