Endotoxin is not a microorganism, and killing the bacteria does not remove it
The limit for a parenteral product is calculable from the dose and the body weight in two lines. Almost nobody in this trade performs the calculation.
Independent testing
Page 24 of 27 of this archive, newest first.
PeptideMeter result on a Changsha liraglutide lot lands 3.8 points below the supplier’s figure
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
Two analysts, one chromatogram, two answers
We work through a single chromatogram twice, under two integration conventions, and show where the difference comes from.
How a claim degrades between the bench and the listing
Every step between the laboratory report and the product page removes information, and the badge is the last step.
Independent analysis puts a Homopeptide cagrilintide lot at 98.1%, against 94.7% on the certificate
The supplier has not disputed the finding. It has not explained the gap either.
Where the solvent front ends is a decision, not a fact
We work through a single chromatogram twice, under two integration conventions, and show where the difference comes from.
Janoshik result on a Suzhou tirzepatide lot lands 4.1 points below the supplier’s figure
The result is unremarkable. What the report omits is not.
Independent analysis puts a HJ orforglipron lot at 95.8%, against 93.6% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
Five things a purity figure cannot tell you
Aggregates dissociate in the mobile phase and are recorded as monomer. Only a size-based separation reports them.
VendorInvestigate result on a Zhuhai survodutide lot lands 0.9 points below the supplier’s figure
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
Independent analysis puts a QST survodutide lot at 96.3%, against 95.4% on the certificate
A reminder that a purity figure is the output of a method, and that methods differ.
We split six vials four ways and posted them
Duplicate submissions under different names test within-laboratory repeatability, which is a different quantity from between-laboratory reproducibility.
PeptideMeter result on a Chengdu exenatide lot lands 3.6 points below the supplier’s figure
The supplier has not disputed the finding. It has not explained the gap either.
Six words a verification badge would need to mean anything
A badge asserts that something was tested. It does not assert what, when, on whose sample, by what method, or whether the lot on sale is the lot that was tested.
Blind duplicates: what happens when a laboratory does not know it is being watched
Duplicate submissions under different names test within-laboratory repeatability, which is a different quantity from between-laboratory reproducibility.
VendorInvestigate result on a Qingdao retatrutide lot lands 3.6 points below the supplier’s figure
A reminder that a purity figure is the output of a method, and that methods differ.
Retest date, expiry date, and the two conventions being confused
A document is only as good as the chain that connects it to the material, and most chains here are two or three links longer than the paperwork admits.
Independent analysis puts a GL Biochem exenatide lot at 98.1%, against 96.5% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.
Same material, different gradients, different answers
Duplicate submissions under different names test within-laboratory repeatability, which is a different quantity from between-laboratory reproducibility.
The number at the bottom of the certificate
A purity percentage is the most quoted figure in the research-peptide trade and one of the least examined. We asked four laboratories to analyse the same vial and got four…