Despite your extensive testing I would strongly advice against using it, due to things you might not be able to detect. A main concern is what we call leachables, molecules that can, well, leach from the material to the product (such as plastifiers, melting agents, etc). Since you are spraying the substance straight to your lungs, the danger level is maximum in terms of contaminants (the regulation regarding extractables and leachable actually started with Metered Dose Inhalers) and I doubt that a plastic designed to melt easily is really fit for this kind of applications. In the industry you would have to track the components of the raw materials and conduct several tests on each part of the device, to insure that it is below accepting doses. And then you would have to account for the sterility aspect of 3D prints...
That being said, very nice design though!
Edit: it is quite similar to why you should use 'microwave OK' plastic only (but in your lungs and with another kind of plastic)
Horny Wan Kenobi