Glossary
Defined as this site uses them, which is narrowly and arithmetically.
Educational arithmetic only. Not medical advice and not a dosing protocol.
Bacteriostatic water
Water containing a preservative, usually benzyl alcohol, intended to inhibit bacterial growth. It is one of the liquids used as a diluent. Nothing on this site says which diluent is appropriate for anything; the arithmetic is the same whatever the liquid is.
Concentration
Mass of compound per unit volume of finished solution, for example 2.5 mg per mL. On this site it is always mass over the FINISHED volume, never mass over the diluent added.
Diluent
The liquid added to a lyophilised solid to dissolve it. Its volume is not the same as the volume of the finished solution.
Displacement
The volume the dissolved solid itself occupies. Finished volume equals diluent plus displacement, so a concentration computed without it is an upper bound.
Graduation
The smallest printed division on a syringe barrel. It sets the finest volume that can be read off that barrel, regardless of how precise the calculation was.
International unit (IU)
A measure of biological activity defined separately for each substance against a reference standard. It is not a unit of mass, and its mass equivalent belongs to a specific preparation.
Lyophilised
Freeze-dried. A lyophilised solid is the powder or cake in an unreconstituted vial.
Molar mass
The mass of one mole of a compound, in grams per mole. Dividing a mass by it gives the molar amount, which is the figure that compares across compounds.
Reconstitution
Dissolving a lyophilised solid in a diluent. The arithmetic of it is on this site; the practice of it is not.
U-100, U-50, U-40
Insulin syringe calibrations, printing 100, 50 or 40 units per millilitre respectively. One unit is 0.01 mL, 0.02 mL or 0.025 mL in turn.
Upper bound
The highest a value can be, given what is known. This site labels a concentration an upper bound when the displacement is unknown, because that is the strongest true statement the inputs support.
Vial strength
The mass of compound stated on the vial label, before any diluent is added.
Read this with the answer
This is educational arithmetic on figures entered by the reader. It is not medical advice, not a dosing protocol, and not a recommendation that anything be prepared, obtained or administered.
Nothing here states what quantity is appropriate for anyone, and there is no function in it that produces an amount to administer. A question about anyone’s health belongs with a licensed clinician who can examine the person asking.
Most compounds named here are research chemicals that are not approved by the FDA for human use. An exact calculation is not an accurate measurement: what is actually in a syringe depends on the preparation and the device, neither of which this page can see.
No qualified clinical reviewer is recorded against this site, and no credential is claimed anywhere on it. Full disclaimer.