PeptideMeter result on a Qingdao cagrilintide lot lands 2.2 points above the supplier’s stated figure

An independent purity determination on cagrilintide material sold by HJ has returned 95.3%, a figure 2.2 percentage points above the number printed on the accompanying certificate, which the supplier had reported against a shorter gradient and a tighter threshold. The analysis was performed by PeptideMeter on a vial the Journal bought as an ordinary retail customer in February 2024 and posted unopened.

Reported figures across the set were: highest 95.3%, lowest 92.4%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 9 of them stated an integration threshold. The Journal has asked the laboratory to publish thresholds on all reports as a matter of routine.

Purity became this trade’s single figure of merit because it is the cheapest measurement to obtain and the easiest to compare. Peptide content, which determines how much drug is actually in a vial, costs several times as much and is quoted as a priced addition by most of the twenty companies in the Journal’s dossier programme rather than carried as a standard release test. Sterility and endotoxin are separate disciplines again, and are neither tested nor claimed.

"Ask for the suitability summary before you argue about the percentage," said Dr Emiko Tanabe, mass spectrometrist. "If the tailing factor and the replicate precision are outside limits, you are arguing about arithmetic performed on an unfit separation."

HJ’s dossier has been updated with this determination and with the company’s response to it. The dossier’s ordering box records the lead times, the minimum quantities and what a buyer should ask for at the point of order.