The question no chromatogram has ever answered
Purity, content, identity, sterility and endotoxin are five separate determinations. A single sheet of paper carrying one of them is not evidence about the other four.
Fill & finish
Page 8 of 11 of this archive, newest first.
Twenty-eight days is a number from somebody else’s product
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…
The reviewer, the approver, and why regulated documents carry two names
What the Journal asks when a document arrives unsigned, and what the answers have been.
Deamidation is the commonest degradation route and the hardest to see
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.
How far back does this document actually reach?
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.
What Janoshik would need in order to certify sterility, and why it does not
The absence of microbiological capability in this market is a commercial fact with a straightforward explanation, and it is worth understanding before blaming anybody for it.
The degradation product that elutes underneath the parent peak
An isoaspartate rearrangement changes the molecule and not the mass. A method that confirms identity by molecular weight alone will report it as the parent compound.
The retest date and the expiry date are not the same document
A stability programme needs a protocol, defined conditions, a stability-indicating method and time. Time is the ingredient no commercial testing service can sell.
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
The sequence predicts the failure mode. A methionine predicts oxidation; an asparagine followed by a glycine predicts deamidation; a cysteine predicts disulphide scrambling.
How a release document is put together in a regulated plant
The header identifies the batch, the table records the tests, and the footer says who is answerable. Two of the three are usually incomplete.
Check the vial, not the box
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.
What the four services actually offer, test by test
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.
Freezing a reconstituted vial: the ice-water interface problem
We set out what is known, what is inferred and what is simply assumed about the fortnight after a vial is opened.
What twenty companies say about storage, and what they have measured
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.
The certificate of analysis, line by line
The purity figure is the least informative line on a well-constructed certificate and the only line most buyers read.
A certificate is a snapshot, and peptides do not stand still
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.
LAL, kinetic chromogenic, recombinant factor C: three ways to the same figure
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.
Everything on the page, in the order a chemist would read it
The header identifies the batch, the table records the tests, and the footer says who is answerable. Two of the three are usually incomplete.
A named analyst is the cheapest quality signal in this trade
What the Journal asks when a document arrives unsigned, and what the answers have been.