My tirz from a weight loss clinic said use within 90 days and it's from South Lake Pharmacy.
I personally prep my syringes. My last vial I got 12 doses out of. But I have a process that limits contamination
*NOTE: This is a watered down/simplified summary and is not meant to be used as a guide for sterile process.
*tie back hair and put on mask
*surgical scrub hands
*sanitize my counter
*get out all supplies, set aside but keep close
*don gloves
*use surgical technique to drape my counter with a sterile drape
*wipe vials with alcohol
*doff gloves
*Don fresh gloves
*wipe top of vial with alcohol
*reconstitute. One hand touches the vial, one hand handles the syringes
*draw up dosages, taking caution to never touch the needle to anything
*put syringes in air tight box in fridge
If I'm adding b12 to my tirz, I use a fresh needle and add it to the syringe with the tirz
so I only have to jab once. Sometimes I may use syringes with removable needles and remove them before storage and put on a fresh one for administering