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.
Testing Dispatch
Medutest result on a Hangzhou liraglutide lot lands 4.1 points above the supplier’s stated figure
A reminder that a purity figure is the output of a method, and that methods differ.
Two laboratories analysing vials from the same liraglutide lot have returned figures 4.1 percentage points apart. Medutest reported 96.1%; VendorInvestigate reported a lower number on a shallower gradient with a tighter integration threshold. Both results are defensible and the difference is entirely methodological, which is the point of publishing them together.
Reported figures across the set were: highest 96.1%, lowest 94.1%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 11 of them stated an integration threshold. The Journal has asked the laboratory to publish thresholds on all reports as a matter of routine.
Reported figures across the set were: highest 96.1%, lowest 94.1%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 11 of them stated an integration threshold. The Journal has asked the laboratory to publish thresholds on all reports as a matter of routine.
Four independent services — Medutest, VendorInvestigate, and the two others operating in this market — carry the analytical burden for a trade that has no release-testing obligation of its own. Each is paid by whoever submits the sample, which is usually the vendor. The Journal’s position is that a submitter-pays model is workable but that its incentive structure has to be stated whenever a result is quoted as verification.
Dr Beatriz Sarmiento, clinical pharmacologist, Universidad de Navarra, said the gap was predictable from the methods alone. "You can reconstruct almost the whole difference from the integration threshold. What you cannot reconstruct is why anyone thinks a number without a threshold is comparable to a number with one."
Homopeptide’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
PeptideMeter result on a Qingdao cagrilintide lot lands 1.4 points above the supplier’s stated figure
A reminder that a purity figure is the output of a method, and that methods differ.
What changed at SGN in June, and what the company says prompted it
Documentation practice is the only part of vendor quality a buyer can assess before purchase.
Independent analysis puts a TFC semaglutide lot at 96.7%, against 94.6% on the certificate
The supplier confirmed the determination and supplied the method behind its own figure inside a week.
Independent analysis puts a QST dulaglutide lot at 95.4%, against 91.5% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.
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.