Why a result on one vial says less than the trade needs it to
The condition on arrival is recorded by some services and not others, and it is one of the more informative lines in a report.
Testing Dispatch
Independent analysis puts a ERP exenatide lot at 95.8%, against 93.5% on the certificate
A reminder that a purity figure is the output of a method, and that methods differ.
A peptide content determination commissioned by the Journal on a 2 mg exenatide vial from ERP has returned 96% of the labelled mass. Chromatographic purity on the same vial was above 95.8%. The two numbers measure different things and only one of them was on the certificate.
The Journal purchased 400 vials from the same lot and had 18 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 95.8%, lowest 93.5%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 18 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.
"The figure is not wrong and neither is theirs," said Yusuf Kandemir, freight and customs broker, Istanbul. "They are answers to two different questions and the trade has decided to pretend there is only one question. Print the gradient and the argument disappears."
ERP’s dossier has been updated with this determination and with the date of the request for comment. The dossier’s "what we could not verify" box records the questions still outstanding.
Related coverage
Reproducibility, measured rather than assumed
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.
Hangzhou export categories for peptide intermediates were quietly renamed
Follow the resin, not the catalogue.
What a laboratory knows about the material it receives
Chain of custody, in a regulated setting, begins at sampling. Here it begins when the package arrives.
The fourteen-day problem, and what it does to a commercial testing model
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.
Independent analysis puts a HJ orforglipron lot at 95.8%, against 93.6% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.