The cake is a record of the cycle that made it
Lyophilisation does not stop degradation. It slows every pathway by removing the solvent that most of them require, and the residue of solvent that remains sets the rate.
Fill & finish
Page 9 of 11 of this archive, newest first.
One vial, four weeks, and the data that does not exist
An in-use period is established by a dedicated study on a specific formulation in a specific container at a specific concentration. Borrowing one from a marketed product is…
The four testing services and the study none of them can run
Storage instructions in this market are close to uniform and almost never accompanied by the study that would justify them. Uniformity is a sign of convention, not of…
The question no chromatogram has ever answered
The Journal has read several hundred certificates from twenty companies. We set out what the documents actually cover, and what a reader is filling in from imagination.
What the sequence tells you about how a peptide will fail
Reversed-phase chromatography runs in an organic, acidic mobile phase that dissociates most non-covalent aggregates on the way to the detector.
Oxidation, and the peroxide that came in with the surfactant
The sequence predicts the failure mode. A methionine predicts oxidation; an asparagine followed by a glycine predicts deamidation; a cysteine predicts disulphide scrambling.
Two decimal places on a single injection is a rhetorical choice
The arithmetic of significant figures, applied to a document that routinely reports four of them.
Collapse temperature, and the hour of the cycle where shelf life is lost
Lyophilisation does not stop degradation. It slows every pathway by removing the solvent that most of them require, and the residue of solvent that remains sets the rate.
Retest date, expiry date, and the two conventions being confused
What happens to traceability when bulk material is subdivided, repackaged and relabelled two or three times before sale.
What we asked twenty suppliers about stability data
We asked twenty companies three questions about stability data and print every answer, refusal and non-response.
The fourteen-day problem, and what it does to a commercial testing model
Endotoxin is the more tractable of the two questions, and a kinetic chromogenic determination is neither slow nor exotic. It is simply not on the menu.
Pass, conform, comply: three words for three different claims
Statements of conformity are supposed to rest on a stated decision rule. Almost nothing in this trade states one.
Check the vial, not the box
The interval between manufacture and analysis is the most under-read figure on the page, and the one most likely to matter by the time a vial is opened.
Benzyl alcohol is a preservative, not a sterilising agent
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.
What we asked twenty suppliers about stability data
A retest date says that material should be re-examined before use. An expiry date says it should not be used. The trade uses the second word for the first concept.
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.
What a batch number is supposed to mean
The interval between manufacture and analysis is the most under-read figure on the page, and the one most likely to matter by the time a vial is opened.
The four testing services and the study none of them can run
What would make a difference is not a regulator. It is three lines on a certificate, all of which are already known to whoever wrote it.
Adsorption, and the dose that stayed on the glass
Bacteriostatic water contains benzyl alcohol at 0.9 per cent, which inhibits microbial growth in a preserved multiple-dose presentation. It does not sterilise a contaminated…
What VendorInvestigate charges to answer the pyrogen question
Bacterial endotoxin is a heat-stable lipopolysaccharide from the outer membrane of Gram-negative organisms. It survives sterilisation, passes a sterilising filter, and is…