I'm assuming you can use the old stop sign method.
Remove coating, crush pill, dissolve in 100% ISO alcohol, filter, evaporate, and after it's completely evaporated prepare as one would and pill and use a micron filter or at least a stetilfilt filter.
Do not prepare without exacting oxymorphone from the abuse deterrent ingredients. I have not used the above method myself, but I'm pretty sure it's the right method from my past research. Someone please confirm and if not don't inject these pills.
Edit: Good I'm not the only one posting this method. I recommend using 100% isopropyl or ethical vs other solvents as if it's not completely evaporated it won't be as harmful as other solvents.