Independent analysis puts a FGP liraglutide lot at 95.7%, against 95.0% on the certificate

PeptideMeter has published a purity determination of 95.7% on a 15 mg vial of liraglutide supplied by FGP, against a figure of 95.0% on the certificate that accompanied the vial. The sample was submitted by the Journal in January 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.

The Journal purchased 16 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.

Batch variance rather than vendor quality is the recurring finding of this programme. Across the 14 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.

"The useful thing in that report is not the percentage, it is the system suitability data," said Dr Wenjun Xie, process chemist and peptide manufacturing consultant. "It is the only part that tells you whether the percentage means anything."

FGP’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.