A cap for a water bottle or other liquid container. The cap has a liquid-dissolvable disk in it that dissolves in the water when the bottle is shaken. The preferred cap also has an annular cavity between inner and outer walls in the sidewall of the cap into which the liquid can flow through fluid passageways...http://www.google.es/patents/US6527109?utm_source=gb-gplus-sharePatente US6527109 - Container cap with liquid-dissolvable additive
