Three services, one lot, and a spread of two and a half points
Duplicate submissions under different names test within-laboratory repeatability, which is a different quantity from between-laboratory reproducibility.
Analytics
Page 22 of 25 of this archive, newest first.
Page 22
Four ways a peptide comes apart
We describe each pathway in enough chemical detail to explain why it is invisible to the method the trade uses, because that is the part which has practical consequences.
Independent analysis puts a WWB survodutide lot at 99.2%, against 95.5% on the certificate
The supplier has not disputed the finding. It has not explained the gap either.
Endotoxin is not a microorganism, and killing the bacteria does not remove it
Three compendial method families are in routine use and a fourth, based on a recombinant enzyme rather than crab lysate, is now compendial in its own right.
Independent analysis puts a WXT semaglutide lot at 98.8%, against 95.3% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
VendorInvestigate result on a Zhuhai dulaglutide lot lands 2.6 points below the supplier’s figure
A reminder that a purity figure is the output of a method, and that methods differ.
Independent analysis puts a QST cagrilintide lot at 98.4%, against 96.0% on the certificate
The supplier has not disputed the finding. It has not explained the gap either.
Quadrupole, time-of-flight, orbital trap: what each class can and cannot see
Every instrument specification quoted in an advertisement is a best case obtained on a calibration mixture, not on a submitted vial.
What the paperwork is for, and who it was designed to protect
The header identifies the batch, the table records the tests, and the footer says who is answerable. Two of the three are usually incomplete.
PeptideMeter result on a Guangzhou orforglipron lot lands 3.3 points below the supplier’s figure
A reminder that a purity figure is the output of a method, and that methods differ.
What a laboratory knows about the material it receives
Chain of custody, in a regulated setting, begins at sampling. Here it begins when the package arrives.
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.
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.
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.
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.
Manual reintegration is legitimate, and it should be declared
We work through a single chromatogram twice, under two integration conventions, and show where the difference comes from.