Independent analysis puts a QST orforglipron lot at 98.0%, against 94.2% on the certificate

VendorInvestigate has released a batch of 4 analytical reports on research-grade orforglipron lots, including material from QST and QSC. Reported purities range across roughly 2.8 percentage points, and the report set is unusual in stating the analytical method for every determination rather than for some of them.

Content by elemental nitrogen determination returned 92% of the labelled nominal mass, which on a 2 mg vial corresponds to roughly 13.48 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 2400 vials from the same lot and had 4 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.

"Content is the number that matters if you are doing arithmetic with a vial, and content is the number nobody sells," said Lorcan Feeney, analytical services director at an independent laboratory. "Purity is what you can afford. Content is what you need."

QST’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.