Maybe look at a feul belt or camelbak where you can carry hydration with you in a more efficient manner for longer runs.  In the alternative, try Nuun or some of the other tablets dissolved in water that might help.  Of course, there are also electrolyte tablets, pills supplements and so on, but I would recommend really taking the time to see if any truly make a difference.  Also, check out Vemma Thirst. 

Hope this helps and best wishes.

Drinking enough before a race is important all right. A hydrated body is a good running body. Just don't over due it...you don't need to load up before a race on fluids like you would a night before carb loading.

http://runnerdude77.blogspot.com

I've been happy with plain old gatorade.