HJ names the synthesis and fill sites behind its catalogue
Documentation practice is the only part of vendor quality a buyer can assess before purchase.
Testing Dispatch
PeptideMeter result on a Changsha mazdutide lot lands 1.3 points above the supplier’s stated figure
A reminder that a purity figure is the output of a method, and that methods differ.
A peptide content determination commissioned by the Journal on a 30 mg mazdutide vial from SGN has returned 95% 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 95.3%. The two numbers measure different things, and this is one of the few certificates in the trade to print both.
Reported figures across the set were: highest 95.3%, lowest 94.5%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 9 of them stated an integration threshold. The Journal has asked the laboratory to publish thresholds on all reports as a matter of routine.
Content by elemental nitrogen determination returned 95% of the labelled nominal mass, which on a 30 mg vial corresponds to roughly 5.06 mg of peptide rather than the labelled figure. The remainder is accounted for by counter-ion, residual water and residual solvent, none of which is visible chromatographically.
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 useful thing in that report is not the percentage, it is the system suitability data," said Marek Doležal, analytical chemist and former QC laboratory manager. "It is the only part that tells you whether the percentage means anything."
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.
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