So I finally got around to trying out my Co better .65/.22 um filters. I filtered 3 milliliters of bacteriostatic water and lost a total of .5 milliliters. However this loss is likely on the high side due to my inexperience. Next time I’ll have to make sure that the container I filter into has a vacuum. A small amount of liquid was lost because the pressure difference between the syringe and the vial led to that liquid shooting back into the syringe at the last second and then out the syringe.
I think with a better technique next time I could probably cut this down to around .3 or .4 milliliters.
I also tested out my HUMAPEN Lily ergo II pen. This was the cheapest pen you can find off of aliexpress that comes with a case. $15 at the link below and that includes free shipping.
https://www.aliexpress.us/item/3256806314136649.html
The pen is compatible with standard insulin cartridges and pen needles. It seems simple enough to use and has the same setup as the pens sold on pep pens or other resellers. It’s not spring loaded and has a dial that can deliver up to 60 units. Definitely a much better deal than buying a similar pen off of one of the resellers.