As promised, here is a work up on how to refill your own Novopen cartridge refills, using a vial from a disposable Levemir pen, and the needle cap from a Lantus Solostar pen.
First off, the big difference to note between the Humapen and the Novopen is that on the Humapen, the needle threads are built onto the pen body, but on the Novopen, the needle thread is part of the actual cartridge.
In the next picture, on the left you can see how the threaded cartridges sticks out of the end of the Novopen.
And on the right side of the picture, an important difference between a salvaged vial from a Solostar pen, and the one from the Levemir pen. The vial from the Levemir is a bit longer, and the Solostar vial is a bit larger diameter. As it turns out, the Solostar vial does not fit properly into the Novopen, but the Levemir vial fits just fine.
So now we need a threaded cap for our salvaged Levemir vial. We can try to use the cap that is on the Levemir disposable, but the plastic is very soft, and the cap fits very loosely, and falls off as soon as the vial is turned over.
But…all those Lantus Solostar pens also have a threaded cap, and the plastic on them is much firmer, and, as it turns out, a much better ‘snap fit’ onto those Levemir vials.
With the Solostar threaded end installed, the salvaged Levemir vial now fits quite nicely in the Novopen, and is ready to be cleaned, filled, and put to work. You can see how closely the newly fabricated vial matches the original.
A couple of notes-
Obviously, if you have Novolog empty cartridges, you just refill them the same way Eric has described for refilling Humalog cartridges.
This trick lets you make your own spares, to fill with whatever you need to fill them with.
You have to have a supply of empty Lantus Solostar and Levemir disposable pens to obtain the required parts.
I noticed that there can be a bit of spinning with the new Lantus caps on the vials. I personally plan to use a tiny drop of CA to address that factor.
Why not just use CA to glue the Levemir cap on instead?
I suppose you could. But the plastic thread on those doesn’t seem to be quite as durable as the threads on the Solostar pens. Plus those are a much nicer fit all the way around.
It occurred to me tonight, that, with so many serviceable parts that can be salvaged from the “disposable” Lantus and Levemir pens, I may just place an ad on the local Craigslist offering to buy empties in lots of 5 or more at a buck for each!