Container closure integrity, and the tests that actually probe it
A sterile product is sterile only for as long as its container closure system excludes the outside world. Integrity is testable, and the tests are cheap by the standards of…
Laboratory Notebook in 2025
Page 2 of 5 of this archive, newest first.
What Medutest charges to answer the pyrogen question
The masking phenomenon known as low endotoxin recovery means a formulation can return a clean result while containing endotoxin the assay cannot see.
EGFR, cystatin C, and the check on the check
The reference interval for alanine aminotransferase in most laboratories is derived from a population that included people with undiagnosed fatty liver.
Fat mass fell more than lean mass. That is the finding, and it is not the headline.
What was pre-specified, what was exploratory, and what was calculated afterwards by people who did not run the trial.
Why a dry powder is a chemical reactor with the volume turned down
Residual moisture is measured routinely in regulated manufacture, is reported almost nowhere in this trade, and predicts long-term stability better than any other single…
The cake tells you something, and it is not purity
Multiple-dose vials are designed for a defined number of punctures. Nobody counts, and the elastomer does not care whether anybody counts.
In-use periods, and the ones nobody can give you
Sharps disposal is a legal obligation in most jurisdictions and a safety obligation everywhere. Household waste is not a route.
Priming a pen is not optional
Aseptic technique here is four steps and none of them are difficult. They are, however, routinely compressed to two.
The out-of-range flag is a statistical convention with a printer attached
Two sources of noise sit under every number: how reproducible the assay is, and how much the analyte varies within the same person on the same day.
The shelf life ends when the diluent goes in
At low concentrations a measurable fraction of peptide can adsorb to glass and plastic surfaces, and the loss is largest exactly where it is least expected.
Asparagine, glycine, and the two residues that decide a shelf life
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.
A reference interval is not a target, and a result outside one is not a diagnosis
Two sources of noise sit under every number: how reproducible the assay is, and how much the analyte varies within the same person on the same day.
Reading the semaglutide composition data without the press release
A substudy powered to describe a mean is not a substudy powered to detect a clinically meaningful individual change.
The substudies, read properly: who was scanned, when, and with what
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.
What VendorInvestigate would need in order to certify sterility, and why it does not
We asked all four services what they can determine, on what timescale, at what price, and under what accreditation. The answers are printed in full.
Two decimal places, one injection, no procedure
Chromatographic purity is cheap, fast and comparable-looking. Those three properties, and not its usefulness, explain why it became the industry’s single figure of merit.
Six lines that would make an identity statement checkable
What the Journal asks for when it writes to a supplier about an identity claim, and how often it gets it.
What happens to a stopper after the fourth needle
Multiple-dose vials are designed for a defined number of punctures. Nobody counts, and the elastomer does not care whether anybody counts.
Bone density during rapid weight loss: what is known, which is less than you would hope
What the Journal would want measured before treating this as settled in either direction.
Sterility is not a percentage, which is the whole difficulty
Every certificate circulating in this market answers a question about molecules. Almost none answers a question about organisms, pyrogens, or the integrity of the seal.