PeptideMeter result on a Wuhan orforglipron lot lands 2.1 points above the supplier’s stated figure

PeptideMeter has released a batch of 13 analytical reports on research-grade orforglipron lots, including material from JEEP and SGN. Reported purities range across roughly 2.1 percentage points, and the report set is unusual in stating the analytical method for every determination rather than for some of them.

Reported figures across the set were: highest 96.3%, lowest 94.2%, 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.

The Journal purchased 10 vials from the same lot at retail and had four 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.

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."

JEEP’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.