VendorInvestigate result on a Shenzhen dulaglutide lot lands 2.0 points below the supplier’s figure

A peptide content determination commissioned by the Journal on a 20 mg dulaglutide vial from MKM has returned 84% of the labelled mass. Chromatographic purity on the same vial was above 97.2%. The two numbers measure different things and only one of them was on the certificate.

Reported figures across the set were: highest 97.2%, lowest 94.5%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 20 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.

"The useful thing in that report is not the percentage, it is the system suitability data," said Sinéad Corrigan, patient advocate and former trial participant. "It is the only part that tells you whether the percentage means anything."

MKM’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.