http://www.egscomics.com/d/20020312.html
No amount of technobabble can adequately explain how something like shrink soda works. I personally think what Germahn Labs specializes in is magitek. Heck, Dr. Germahn even refers to his concoction in this strip as a "potion".
Incidentally, what do you suppose happens to a person's voice when they are shrunk like that? Does it get higher pitched or quieter? Or possibly both?