Independent analysis puts a SGN survodutide lot at 97.0%, against 92.8% on the certificate

A peptide content determination commissioned by the Journal on a 10 mg survodutide vial from SGN has returned 92% 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 97.0%. The two numbers measure different things, and this is one of the few certificates in the trade to print both.

The Journal purchased 18 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.

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.

"The figure is not wrong and neither is theirs," said Marek Doležal, analytical chemist and former QC laboratory manager. "They are answers to two different questions and the trade has decided to pretend there is only one question. Print the gradient and the argument disappears."

SGN’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.