Sort of. Some drugs lend themselves quite well to certain states, and the vector helps to target specific areas. Asthma inhalers spring to mind.
I'm not sure why you'd want to change all this, but my lack of creativity shouldn't inhibit yours! DMSO may allow for contact vector, but injecting a contact vectored toxin would be... problematic. It might work way too well, and making your blood "contact vector" can't be good for your health. I would not recommend this if you're doing an extraction.
Getting it to be inhaler friendly would be VERY hard. There's a reason they don't make Narcogas, and Neurostun is so expensive and rare. It is easy to vaporize, but it is really, really hard to make it stay gaseous down to 10 degrees celcius (it wouldn't be very useful if a cool spring evening rendered your plan null). Using a DMSO variant you could make a liquid condense into a powdery contact solid for an inhaler, since that thing basically just dusts your lungs.
Keep us posted on any house rules you develop. This is a neat idea.