LAL, kinetic chromogenic, recombinant factor C: three ways to the same figure
We submitted vials for endotoxin determination and report the results, the method and the laboratory, because a pyrogen figure without a method is as empty as a purity…
Testing Dispatch
Independent analysis puts a WWB liraglutide lot at 98.2%, against 96.5% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
An independent purity determination on liraglutide material sold by WWB has returned 98.2%, a figure 4.1 percentage points above the number printed on the accompanying certificate, which the supplier had reported against a shorter gradient and a tighter threshold. The analysis was performed by PeptideMeter on a vial the Journal bought as an ordinary retail customer in February 2024 and posted unopened.
The Journal purchased 17 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.
The Journal purchased 17 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."
WWB’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.
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