Filtering peptides

Why filter

A 0.22 µm filter removes bacteria and particles that may be in a vial or got in while mixing. It is an extra layer of safety. It does not remove endotoxins, impurities in the peptide itself, or fix a vial that holds the wrong amount or the wrong peptide.

Filter after mixing. Filtering only the water on its way into the vial cleans the water, not the powder.

• Use a sterile, individually wrapped 0.22 µm PES or PVDF filter with luer-lock ends. 13 mm filters hold back less liquid than 25 mm.
• One filter per use. Never reuse one.
• A little liquid stays in the filter and syringe. The strength doesn't change; you just get slightly fewer doses. Pushing a little air through at the end clears most of it.
• Push slowly and steadily. If it suddenly gets very hard to push, stop: the filter is clogged. Forcing it can tear the membrane. Finish with a new filter.

Method A: into a sterile empty vial

Best when one vial will fill more than one cartridge, or when you dose with syringes.

1. 1Mix the peptide as usual in its own vial.
2. 2Swab the peptide vial and the sterile empty vial stoppers. Let them dry.
3. 3With a 3 mL luer-lock syringe and a drawing needle, draw out all the liquid. Tip the vial so the needle tip stays in the liquid.
4. 4Unscrew the drawing needle (into the sharps container). Screw the filter onto the syringe, and a fresh needle onto the filter's outlet.
5. 5Push the needle into the empty vial. If it isn't under vacuum, add a venting needle so air can escape.
6. 6Press slowly until the syringe is empty, then push a little air through to clear the filter.
7. 7Label the new vial: peptide, concentration (same as before), date, "filtered". Dose from this vial.

Method B: straight into a pen cartridge

Best when one vial fills one cartridge: one fewer transfer and fewer punctures.

1. 1Mix the peptide and draw out the amount for the cartridge (the Pen calculator says how much).
2. 2Swap the drawing needle for the filter, with a fresh needle on the filter's outlet.
3. 3Fill the cartridge exactly as in Filling a pen cartridge, pushing through the filter slowly, with a venting needle if your cartridge needs one.

Go with this guide