Is it Taylor Dispersion or Something Similar in Drug Injection?

[paxprobellum]

I'm having a wording issue in a paper I'm writing. Specifically, I'm trying to decide between arguing something is "diffusion" vs. "dispersion". Can anyone point me to a reference that clearly demarcates between these?

In specific, I'm referring to the diffusion/dispersion of an injected drug in the bloodstream.

 

[Andy Resnick]

Interesting question. The nomenclature is rather loose on this point, but I wonder if you are describing Taylor dispersion, or something similar:

http://en.wikipedia.org/wiki/Taylor_dispersion