Can't you just wet it using bac water? Draw 3 ml bac into a syringe, put 1 ml into the peptide vial, send 1 ml through the filter into a donor vial, pull the reconstituted peptide into another syringe and push it through the filter, then use the last ml of bac to rinse the filter.
I watched some peptide filtering videos and one on STG showed adding diluent to the filter first to wet it, letting it sit while getting everything else ready, then using it on the combined peptides. Has anyone else seen this step, and is it useful or worth doing? Filters have clogged or broken on me before, so I wondered if wetting them ahead of time might help.