Draw the reconstituted peptide from the original vial into a luer-lock syringe.
Attach the PES syringe filter to the syringe.
Attach a needle to the filter output.
Push the liquid through the filter into a new sterile vial (or pen cartridge).
Use a vent needle (just a needle, no syringe) in the receiving vial to equalize pressure.
Air-purge the filter at the end: draw air into the syringe and push it through to recover residual liquid from the filter.
Detailed video tutorials are available on the Peptide Test YouTube channel.