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Watch: how to mix a vial (90 sec)
Captions are built in, so it works with the sound off.
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Step-by-step handling basics
General guidance only. Your supplier's documentation always comes first.
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Clean the tops
Wash your hands. Wipe the rubber top of the vial and the water vial with a fresh alcohol swab and let them air-dry.
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Add water slowly down the side
Draw up the bacteriostatic water. Insert the needle at an angle and let the water run slowly down the inside wall of the vial, not straight onto the powder.
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Swirl gently, don't shake
Roll the vial between your fingers or swirl it slowly until fully dissolved. Shaking can create foam and may damage delicate contents. Give it a few minutes if needed.
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Store it properly
After mixing, most reconstituted products are generally kept refrigerated and protected from light. Don't freeze unless your supplier says to. Follow the supplier's documentation for exact storage.
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Label the vial
Write the date you mixed it and the concentration (for example "2.5 mg/mL – 25 mcg per unit"). Future you will thank you.
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Know when to throw it out
Discard the vial if the liquid looks cloudy, has particles or floaters, has changed color, or is past the use window stated by the supplier.
How the math works
- Concentration = amount in vial ÷ water added (mL).
- Per unit = concentration ÷ 100, because a U-100 syringe holds 100 units in 1 mL.
- Units to draw = amount wanted ÷ concentration × 100.
- Water to add = vial amount × (units ÷ 100) ÷ amount wanted.
- 1 mg = 1,000 mcg.
Example: 5 mg vial + 2 mL water = 2.5 mg/mL = 25 mcg per unit. So 250 mcg = 10 units = 0.10 mL.