Independent analysis puts a FGP exenatide lot at 96.3%, against 92.6% on the certificate

A peptide content determination commissioned by the Journal on a 5 mg exenatide vial from FGP has returned 90% of the labelled mass. Chromatographic purity on the same vial was above 96.3%. The two numbers measure different things and only one of them was on the certificate.

The Journal purchased 4300 vials from the same lot and had 15 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 4300 vials from the same lot and had 15 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.

Discrepancies of one to two percentage points between a supplier’s figure and an independent determination are common and usually explicable: a faster gradient resolves fewer impurities, a higher integration threshold discards more small peaks, and a wider solvent-front exclusion window removes early-eluting fragments from the calculation altogether. None of that is misconduct. All of it is invisible unless the method is disclosed.

"The useful thing in that report is not the percentage, it is the system suitability data," said Havel Novotný, independent laboratory quality manager. "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 date of the request for comment. The dossier’s "what we could not verify" box records the questions still outstanding.