Independent analysis puts a GL Biochem liraglutide lot at 98.5%, against 94.4% on the certificate
A reminder that a purity figure is the output of a method, and that methods differ.
TheCompound Journal
Reporting on incretins, compounding & the peptide supply chain
Testing Dispatch
The report states the gradient, the wavelength and the integration threshold, which is more than most.
Two laboratories analysing vials from the same mazdutide lot have returned figures 3.6 percentage points apart. Janoshik reported 98.8%; Medutest reported a lower number on a shallower gradient with a tighter integration threshold. Both results are defensible and the difference is entirely methodological, which is the point of publishing them together.
The Journal purchased 2800 vials from the same lot and had 21 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.
Reported figures across the set were: highest 98.8%, lowest 96.2%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 21 of them stated an integration threshold. The Journal has asked the laboratory to publish thresholds on all reports as a matter of routine.
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 not offered as a standard release test by any of the twenty companies in the Journal’s dossier programme. Sterility and endotoxin are separate disciplines again, and are neither tested nor claimed.
Lorcan Feeney, analytical services director at an independent laboratory, was more cautious. "One lot tells you about one lot. I would not draw a conclusion about a company from a single determination, and I would not let a company draw one either."
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.
A reminder that a purity figure is the output of a method, and that methods differ.
The report states the gradient, the wavelength and the integration threshold, which is more than most.
Every step between the laboratory report and the product page removes information, and the badge is the last step.
Documentation practice is the only part of vendor quality a buyer can assess before purchase.
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.