VendorInvestigate result on a Wuhan orforglipron lot lands 3.8 points above the supplier’s stated figure

A peptide content determination commissioned by the Journal on a 2 mg orforglipron vial from SWB has returned 95% of the labelled mass, the balance being the counter-ion and residual water that every lyophilised salt carries. Chromatographic purity on the same vial was above 95.9%. The two numbers measure different things, and this is one of the few certificates in the trade to print both.

Content by elemental nitrogen determination returned 95% of the labelled nominal mass, which on a 2 mg vial corresponds to roughly 10.12 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 Journal purchased 14 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.

Four independent services — VendorInvestigate, Medutest, and the two others operating in this market — carry the analytical burden for a trade that has no release-testing obligation of its own. Each is paid by whoever submits the sample, which is usually the vendor. The Journal’s position is that a submitter-pays model is workable but that its incentive structure has to be stated whenever a result is quoted as verification.

Dr Wenjun Xie, process chemist and peptide manufacturing consultant, wanted the wavelength printed. "A method reading at 280 nanometres cannot see a fragment that has lost its aromatic residue. That is not a failure of the laboratory, it is a fact about the question they were asked."

SWB’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.