The fourteen-day problem, and what it does to a commercial testing model
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.
Reconstitution
Page 5 of 12 of this archive, newest first.
What a 1 mL syringe does that a 0.3 mL syringe does not
A unit is a volume. A dose is a mass. The bridge between them is concentration, and concentration is a number somebody has to calculate.
LAL, kinetic chromogenic, recombinant factor C: three ways to the same figure
We submitted vials for endotoxin determination and report the results, the method and the laboratory, because a pyrogen figure without a method is as empty as a purity…
How a correct calculation becomes a wrong dose
Almost every case involves a change — a new vial, a new syringe size, a new supplier — carried forward with an old number.
A unit is not a dose, and it never was
The graduation interval differs between barrel sizes, and a 1 mL barrel is frequently marked in two-unit steps. Reading one as though it were marked in single units halves…
How to read the silence on a certificate you already hold
Our position is about documentation practice. It is not an allegation about anybody’s honesty, and we are explicit about the difference.
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…
Gauge, pain and flow rate
The insulin injection-technique literature is large, well conducted and directly transferable on questions of depth and tissue. We say where it stops transferring.
Storage after reconstitution, and the evidence behind the numbers
A needle blunts on first use. Reuse is uncomfortable, and it is a documented contributor to lipohypertrophy.
LAL, kinetic chromogenic, recombinant factor C: three ways to the same figure
We submitted vials for endotoxin determination and report the results, the method and the laboratory, because a pyrogen figure without a method is as empty as a purity…
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.
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…
Same mass, different molecule: why identity by mass is not identity
Reversed-phase chromatography runs in an organic, acidic mobile phase that dissociates most non-covalent aggregates on the way to the detector.
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.
Units, millilitres, milligrams: three scales on one small object
We work through the arithmetic in full, because it is short, and because the errors it prevents are order-of-magnitude errors.
Hydrolysis, isomerisation, and the arithmetic of a broken bond
Deamidation, oxidation, aggregation and hydrolysis account for nearly all of what happens to a peptide over time. Each has a characteristic residue, a characteristic…
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.
A vial can be 99.4 per cent pure and not sterile in the same afternoon
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.
Endotoxin is not a microorganism, and killing the bacteria does not remove it
Three compendial method families are in routine use and a fourth, based on a recombinant enzyme rather than crab lysate, is now compendial in its own right.
From milligrams in a vial to units in a barrel
A more concentrated reconstitution means smaller injection volumes, which means larger proportional errors from graduation, dead space and technique.