The header, the table and the signature block
The header identifies the batch, the table records the tests, and the footer says who is answerable. Two of the three are usually incomplete.
Testing Dispatch
VendorInvestigate result on a Shenzhen dulaglutide lot lands 1.9 points below the supplier’s figure
The supplier has not disputed the finding. It has not explained the gap either.
Two laboratories analysing vials from the same dulaglutide lot have returned figures 1.9 percentage points apart. VendorInvestigate reported 95.6%; Janoshik 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 95.6%, lowest 91.7%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 6 of them stated an integration threshold. The Journal has asked the laboratory to publish thresholds on all reports as a matter of routine.
Content by elemental nitrogen determination returned 85% of the labelled nominal mass, which on a 20 mg vial corresponds to roughly 10.97 mg of peptide rather than the labelled figure. The remainder is accounted for by counter-ion, residual water and residual solvent, none of which is visible chromatographically.
The wider context is that material sold for research use carries no regulatory release specification in any jurisdiction the Journal has examined. A certificate is a commercial document, not a compliance one, and its content is whatever the issuer chooses to put on it. That is the gap independent testing fills, and it fills it imperfectly.
Alastair Renshaw, pharmaceutical supply-chain consultant, 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."
JEEP’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.
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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.