VendorInvestigate result on a Hangzhou dulaglutide lot lands 2.2 points above the supplier’s stated figure

VendorInvestigate has released a batch of 7 analytical reports on research-grade dulaglutide lots, including material from TFC and FGP. Reported purities range across roughly 2.2 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 96% of the labelled nominal mass, which on a 10 mg vial corresponds to roughly 12.86 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.

Reported figures across the set were: highest 95.2%, lowest 91.5%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 7 of them stated an integration threshold. The Journal has asked the laboratory to publish thresholds on all reports as a matter of routine.

Batch variance rather than vendor quality is the recurring finding of this programme. Across the 7 determinations the Journal has commissioned to date, within-vendor spread has been wider than between-vendor spread for two thirds of the companies tracked, which is an argument against rating any supplier on a single number.

Dr Emiko Tanabe, mass spectrometrist, 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."

TFC’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.