From vial to bench: what is recorded and what is assumed
The condition on arrival is recorded by some services and not others, and it is one of the more informative lines in a report.
Nikolaj Brandvold
Page 6 of 7 of this archive, newest first.
Archive — page 6
123 piecesThe intramuscular injection nobody intended
The insulin injection-technique literature is large, well conducted and directly transferable on questions of depth and tissue. We say where it stops transferring.
Micronutrient monitoring: which panel, how often, and on whose evidence
What the trials measured, which in the case of micronutrients is very little.
Independent analysis puts a CPC orforglipron lot at 95.2%, against 92.3% on the certificate
A reminder that a purity figure is the output of a method, and that methods differ.
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.
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.
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.
How a release document is put together in a regulated plant
Nothing on this page is difficult. It is simply unfamiliar, and unfamiliarity is what makes a weak certificate look like a strong one.
Matrix, laser, needle: the plumbing that determines what you see
A brief and unromantic tour of the interface between a liquid sample and a vacuum.
Independent analysis puts a SWB dulaglutide lot at 96.2%, against 95.6% on the certificate
The report states the gradient, the wavelength and the integration threshold, which is more than most.
Soft ionisation: the twenty-year-old trick that made peptide identity routine
A brief and unromantic tour of the interface between a liquid sample and a vacuum.
How a correct calculation becomes a wrong dose
Almost every case involves a change — a new vial, a new syringe size, a new supplier — carried forward with an old number.
Independent analysis puts a BCH cagrilintide lot at 96.1%, against 95.2% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
Site selection when the tissue has already changed
A rotation scheme that is too complicated will not be followed. We describe the simple ones that are.
What happens in solution that does not happen in the cake
Every degradation pathway accelerates by orders of magnitude on reconstitution, because the solvent that lyophilisation removed is the reagent most of them need.
What a 1 mL syringe does that a 0.3 mL syringe does not
We work through the arithmetic in full, because it is short, and because the errors it prevents are order-of-magnitude errors.
Reading the semaglutide composition data without the press release
The composition data comes from imaging substudies enrolling a few score participants at selected sites. It is the best evidence available and it is thin.
Sixteen daltons: methionine, and the easiest degradation to find
Deamidation adds 0.98 daltons. On a low-resolution instrument at incretin molecular weights, that is inside the noise.
Site selection when the tissue has already changed
A rotation scheme that is too complicated will not be followed. We describe the simple ones that are.
Independent analysis puts a FGP liraglutide lot at 95.7%, against 95.0% on the certificate
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.