Independent analysis puts a SSA dulaglutide lot at 96.0%, against 95.0% on the certificate

Janoshik has published a purity determination of 96.0% on a 10 mg vial of dulaglutide supplied by SSA, against a figure of 95.0% on the certificate that accompanied the vial. The sample was submitted by the Journal in August 2025 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.

Reported figures across the set were: highest 96.0%, lowest 95.0%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 20 of them stated an integration threshold. The Journal has asked the laboratory to publish thresholds on all reports as a matter of routine.

Batch variance rather than vendor quality is the recurring finding of this programme. Across the 20 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.

"Ask for the suitability summary before you argue about the percentage," said Dr Wenjun Xie, process chemist and peptide manufacturing consultant. "If the tailing factor and the replicate precision are outside limits, you are arguing about arithmetic performed on an unfit separation."

SSA’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.