Endotoxin dose-limit calculator
The K/M calculation: from a body mass and a dose, the endotoxin concentration a material may carry, and whether a measured figure is inside it.
The index's own acceptance figure of 5 EU/mg is a convention that makes records comparable with each other. It is not a limit. A real limit is the calculation on this page, and it depends on the dose — which is why the index cannot publish one.
The arithmetic
endotoxin permitted per hour (EU) = K (EU/kg/h) × body mass (kg) permitted concentration (EU/mg) = permitted EU ÷ dose (mg) delivered (EU) = measured (EU/mg) × dose (mg)
Why an EU/mg figure alone means nothing
Endotoxin limits are dose-dependent, not concentration-dependent. The same 2 EU/mg material is comfortably inside any sane limit at a 100 µg dose and outside it at a 50 mg dose. A certificate stating "endotoxin: 2.1 EU/mg" is therefore not a pass or a fail; it is an input to a calculation that only the person administering the material can complete.
K is the threshold pyrogenic dose per kilogram per hour, and it is route-dependent: 5.0 EU/kg/h for ordinary parenteral routes, 0.2 for intrathecal — a twenty-five-fold difference that reflects the absence of the hepatic and pulmonary clearance the bloodstream provides. M is the maximum dose administered in one hour.
What an endotoxin figure does not cover
- Sterility. Endotoxin is a heat-stable fragment of Gram-negative bacterial cell wall. It is present whether the bacteria are alive or long dead, and a sterile preparation can carry a great deal of it. The two tests answer different questions and sterility is the other one.
- Gram-positive contamination. LAL responds to lipopolysaccharide. A material heavily contaminated with a Gram-positive organism can return a clean endotoxin result.
- Anything a chromatogram measures. Purity, identity and content bear on endotoxin not at all, and vice versa. 4,926 of 6,722 records in this index carry no endotoxin figure, and for those the property is simply unknown.