VendorInvestigate result on a Xianning cagrilintide lot lands 2.6 points above the supplier’s stated figure

VendorInvestigate has released a batch of 6 analytical reports on research-grade cagrilintide lots, including material from GL Biochem and HJ. Reported purities range across roughly 2.6 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 95.6%, lowest 93.1%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 6 of them stated an integration threshold. The Journal has asked the laboratory to publish thresholds on all reports as a matter of routine.

Content by elemental nitrogen determination returned 93% of the labelled nominal mass, which on a 20 mg vial corresponds to roughly 4.25 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.

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.

Dr Beatriz Sarmiento, clinical pharmacologist, Universidad de Navarra, 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."

GL Biochem’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.