I really have to ask, and I think it may have been answered in a different tread, so I apologize for the redundancy - why do you want to IV this stuff? Other than that it is perfectly prep'd for that use?
I take diazepam daily and cannot see any benefit to IV-ing it, although not to do so with those ampules I admit would be a bit difficult myself - as I have all the gear here ready to go. And it would be so easy - so if it was curiosity I get that for certain!
It's oral BA as stated in the other thread is near 100%. 90%+ I believe, fatty food does have an effect but does not diminish total BA, just stretches the half-life a bit and lowers the peak w/ fatty food. A liquid prep might not be subject to these effects, it might be a more predictable dosing method? Similar to PG solutions of RC benzos.
Obviously with IV you'll hit peak diazepam conc. very quickly - is there a "rush" to this? I doubt it but I don't know.
Is it a needle fetish thing? If so I get that, when I was young and stupid - really being stupid b/c my career had taught me differently - I tried to shot up diazepam out of a water solution! All I got was filler and blue dye! Once and never tried again.
So, I've come to understated it doesn't matter for drug effect unless you're IV-ing it with an opioid - which would be a (near) definite suicide, so why shoot it at all?
Just curious, really - I use drgs in fucked up ways that don't make sense sometimes, so... I think I'll undersatnd the answer, not being critical.