Oxidation, and the peroxide that came in with the surfactant
Deamidation, oxidation, aggregation and hydrolysis account for nearly all of what happens to a peptide over time. Each has a characteristic residue, a characteristic…
Reconstitution
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Bacteriostatic water, sterile water, and the 0.9 per cent that makes the difference
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…
A vial can be 99.4 per cent pure and not sterile in the same afternoon
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.
Same mass, different molecule: why identity by mass is not identity
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 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.
What Medutest would need in order to certify sterility, and why it does not
A compendial sterility test takes fourteen days of incubation and consumes the containers tested. That timescale is incompatible with the business model that made…
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.
A unit is not a dose, and it never was
Dead space in the needle hub is a real and calculable loss, and it matters more at small volumes than anybody expects.
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.
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.
Why the independent testing market grew a chemistry arm and not a microbiology one
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 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.
What VendorInvestigate is able to certify about a sealed vial, and what it is not
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.
Four millimetres is enough, and the data says so
The insulin injection-technique literature is large, well conducted and directly transferable on questions of depth and tissue. We say where it stops transferring.
The one place the insulin literature and this class agree completely
Repeated injection into the same small area produces lipohypertrophy — thickened, rubbery subcutaneous tissue with blunted and erratic absorption. It is common, it is…
What the four services actually offer, test by test
A compendial sterility test takes fourteen days of incubation and consumes the containers tested. That timescale is incompatible with the business model that made…
Asparagine, glycine, and the two residues that decide a shelf life
Deamidation, oxidation, aggregation and hydrolysis account for nearly all of what happens to a peptide over time. Each has a characteristic residue, a characteristic…
We asked four laboratories for a sterility test. Here is what came back.
A compendial sterility test takes fourteen days of incubation and consumes the containers tested. That timescale is incompatible with the business model that made…
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.