Medutest result on a Qingdao orforglipron lot lands 0.8 points below the supplier’s figure

A peptide content determination commissioned by the Journal on a 20 mg orforglipron vial from QSC has returned 90% of the labelled mass. Chromatographic purity on the same vial was above 97.6%. The two numbers measure different things and only one of them was on the certificate.

The Journal purchased 1200 vials from the same lot and had 13 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 97.6%, lowest 94.6%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 13 of them stated an integration threshold. The Journal has asked the laboratory to publish thresholds on all reports as a matter of routine.

Discrepancies of one to two percentage points between a supplier’s figure and an independent determination are common and usually explicable: a faster gradient resolves fewer impurities, a higher integration threshold discards more small peaks, and a wider solvent-front exclusion window removes early-eluting fragments from the calculation altogether. None of that is misconduct. All of it is invisible unless the method is disclosed.

Sinéad Corrigan, patient advocate and former trial participant, 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."

QSC’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.