How to reconstitute.
Reconstitution is a technique, not a recipe. The ratios belong to whatever you are reconstituting; the technique below is the part that stays the same every time and is where most avoidable problems come from.
Set the bench up first
Clean, dry surface. Everything you need within reach before anything is opened: the vial, the diluent, a fresh syringe, and alcohol prep pads. The moment you are hunting for a second pad mid-procedure is the moment the sterile field stops being sterile. Wash and dry hands, and let them dry fully — damp hands defeat the point.
Disinfect both stoppers, every time
Wipe the stopper of the vial AND the stopper of the diluent with a fresh 70% isopropyl pad — one pad per stopper, never the same pad twice. Then let both air-dry. The alcohol does its work while it is wet and evaporating, so piercing a wet stopper drags liquid inward and skips the disinfection entirely. Do not fan, blot, or blow on it.
Draw the diluent
Draw your target volume of diluent into the syringe. Pull slightly past the mark, tap the barrel to bring bubbles to the top, and push back down to the line — air in the barrel is volume you think you are adding and are not. Choice of diluent depends entirely on what you are reconstituting and its labeling: bacteriostatic water is the common case for a multi-dose vial, sterile water for single use, and an acidic diluent only where the labeling calls for one.
Add it slowly, down the glass
Angle the needle so the stream runs down the inside wall of the vial rather than jetting directly onto the powder. Let it flow in under gentle pressure. Firing diluent straight into the cake is the single most common way to damage the contents at this stage, and it is entirely avoidable.
Swirl — never shake
Roll the vial gently between your fingers, or swirl it flat on the bench, until the solution is clear. This can take a minute or two and that is normal. Shaking introduces shear force and foams the solution; foam is both a sign of stress on the contents and a practical problem, since you cannot draw an accurate volume through it. If it foams, set it down and let it settle before doing anything else.
Look at it before you use it
A correctly reconstituted solution should be clear and free of visible particulate. Cloudiness, floaters, discolouration, or anything that has not gone into solution after adequate gentle swirling are all reasons to stop and reassess rather than proceed.
Label and store it
Write the reconstitution date on the vial before it goes anywhere. Storage conditions and in-use shelf life come from the labeling of the specific product — not from a general rule of thumb, and not from what the last vial did. Wipe the stopper with a fresh pad before every subsequent draw, not just the first.
What the bench needs
- BAC water — preserved diluent for multi-dose vials
- Reconstitution syringes — sterile, single-use
- Alcohol prep pads — one per stopper, every draw
- Acetic acid — only where the labeling calls for an acidic diluent
Common questions
- Why bacteriostatic water instead of sterile water?
- Bacteriostatic water contains 0.9% benzyl alcohol as a preservative, which is what allows a multi-dose vial to be pierced repeatedly over a period of days without the contents becoming a growth medium. Sterile water has no preservative and is intended for single use. Which one is appropriate is determined by the labeling of what you are reconstituting.
- Why does swirling matter so much?
- Shaking applies shear force and introduces air. Beyond the risk to the contents themselves, foam sits on top of the solution and makes accurate volume draws impossible until it settles. Gentle swirling gets you to the same clear solution without either problem — it just takes slightly longer.
- Do I really need a fresh alcohol pad for every single draw?
- Yes. The rubber stopper is the only barrier between the vial contents and the room, and it is being pierced repeatedly. Wiping it with a fresh pad before every draw is what keeps that barrier meaningful for the life of the vial. Pads are the cheapest thing on the bench and the most consequential to skip.
- How much diluent should I add?
- That is determined entirely by the labeling of the product being reconstituted and by clinical judgement. SBB Supply distributes bench consumables and does not provide reconstitution ratios, dosing guidance, or protocols for any specific product.
- What if the solution stays cloudy?
- Do not use it. Persistent cloudiness, visible particulate, or material that will not go into solution after adequate gentle swirling all warrant stopping and reassessing rather than proceeding.
SBB Supply is an authorized distributor of finished bench consumables. This page describes general handling technique for those consumables. It is not clinical guidance, not a protocol, and makes no claim about any specific drug product — reconstitution ratios, storage limits, and suitability are determined by the labeling of what you are reconstituting and by the clinician.