Reconstitution & Vials
Reconstitution
Definition
The process of adding a liquid to a dry or lyophilized product so that it becomes a solution or suspension with a calculable concentration.
What Reconstitution means
From a math perspective, reconstitution creates a relationship between the amount in the vial and the final liquid volume. That relationship is expressed as concentration.
Why the distinction matters
BACToBasics focuses on the arithmetic that follows from user-entered values. It does not determine whether a product should be reconstituted, which diluent should be used, or how a product should be prepared clinically.
Common confusion
Changing liquid volume changes concentration and draw volume, but it does not change the total labeled mass that was originally in the vial.
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Open the BACToBasics tools and reference pages where this term is used.
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Related glossary terms
Reconstitution & Vials
Lyophilized
Freeze-dried: a form in which water has been removed from a product under controlled conditions.
Math & Measurement
Concentration
The amount of a substance contained in a given volume of liquid, such as mg/mL or mcg/mL.
Reconstitution & Vials
Bacteriostatic Water
Sterile water for injection that contains an antimicrobial preservative intended to inhibit bacterial growth after entry into the vial.
Reconstitution & Vials
Sterile Water
Sterile water for injection that does not contain the bacteriostatic preservative found in bacteriostatic water.
Published September 6, 2026. BACToBasics glossary pages are educational definitions only and do not provide medical, dosing, preparation, treatment, or product-selection advice.