Interesting, I have use soluble aspirin before.
The Scientist to my right says that as soon as the water hits the medium, it will cede bubbles off CO2 and immediately remove fizz from water.Surely the theory works in a similar way to how humans get hammered faster on "fizzy" alcoholic drinks than on "still" ones, the bubbles increase the absorption of alcohol into the bloodstream so the hooch hits faster and harder.