Medutest result on a Xianning survodutide lot lands 4.4 points below the supplier’s figure

Two laboratories analysing vials from the same survodutide lot have returned figures 4.4 percentage points apart. Medutest reported 97.1%; PeptideMeter 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.

Content by elemental nitrogen determination returned 93% of the labelled nominal mass, which on a 30 mg vial corresponds to roughly 13.75 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."

Homopeptide’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.