Twenty-eight days is a number from somebody else’s product
We set out what is known, what is inferred and what is simply assumed about the fortnight after a vial is opened.
Reconstitution
Page 11 of 12 of this archive, newest first.
Gauge, pain and flow rate
Skin thickness at the standard injection sites is approximately two millimetres in adults and varies remarkably little with body mass. That single finding is why short…
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.
Aggregation: the impurity your chromatogram dissolved before it looked
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.
Why a dead-clean sterile filter can pass pyrogen straight through
Bacterial endotoxin is a heat-stable lipopolysaccharide from the outer membrane of Gram-negative organisms. It survives sterilisation, passes a sterilising filter, and is…
LAL, kinetic chromogenic, recombinant factor C: three ways to the same figure
Bacterial endotoxin is a heat-stable lipopolysaccharide from the outer membrane of Gram-negative organisms. It survives sterilisation, passes a sterilising filter, and is…
Low endotoxin recovery: the interference nobody looks for
The masking phenomenon known as low endotoxin recovery means a formulation can return a clean result while containing endotoxin the assay cannot see.
Why FGP can be entirely straightforward and still tell you nothing about bioburden
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.
The site you keep using is the site that stops working
Repeated injection into the same small area produces lipohypertrophy — thickened, rubbery subcutaneous tissue with blunted and erratic absorption. It is common, it is…
In-use stability is a separate study, and almost nobody has done it
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…
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.
Janoshik, Medutest, PeptideMeter, VendorInvestigate: a capability audit
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.
Adsorption, and the dose that stayed on the glass
Every degradation pathway accelerates by orders of magnitude on reconstitution, because the solvent that lyophilisation removed is the reagent most of them need.
The cold chain in this trade is a gel pack and an optimistic estimate
A gel pack has a finite thermal budget, and once it is spent the payload equilibrates with whatever is outside the box. The only question is how long that takes.
The retest date and the expiry date are not the same document
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.
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.
Lipohypertrophy, and the absorption it ruins
A rotation scheme that is too complicated will not be followed. We describe the simple ones that are.
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.
What a 1 mL syringe does that a 0.3 mL syringe does not
Dead space in the needle hub is a real and calculable loss, and it matters more at small volumes than anybody expects.
Two documents, two disciplines: purity and sterility are not the same trade
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.