What changed at SWB in June, and what the company says prompted it
Documentation practice is the only part of vendor quality a buyer can assess before purchase.
Testing Dispatch
VendorInvestigate result on a Qingdao retatrutide lot lands 3.6 points above the supplier’s stated figure
A reminder that a purity figure is the output of a method, and that methods differ.
VendorInvestigate has published a purity determination of 99.1% on a 20 mg vial of retatrutide supplied by MKM, against a figure of 96.9% on the certificate that accompanied the vial. The sample was submitted by the Journal in April 2024 as part of a continuing programme of arm’s-length purchasing, and the vendor was told before the order was placed that any result would be published.
Content by elemental nitrogen determination returned 93% of the labelled nominal mass, which on a 20 mg vial corresponds to roughly 4.53 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 13 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.
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.
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."MKM’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.
Related coverage
Who signed this, and what did they undertake by signing it
Two signatures — one who performed the work, one who approved its release — are the ordinary regulated convention and are almost unknown here.
What changed at SGN in March, and what the company says prompted it
Documentation practice is the only part of vendor quality a buyer can assess before purchase.
Holograms, QR codes and other things that are not verification
Reported from the analysis, not from a warning notice.
Independent analysis puts a ERP orforglipron lot at 98.6%, against 97.6% on the certificate
The result is unremarkable. What the report states alongside it is not.
VendorInvestigate result on a Zhuhai survodutide lot lands 4.2 points above the supplier’s stated figure
The supplier confirmed the determination and supplied the method behind its own figure inside a week.