I think as long as you're not leaving the bottle in a hot spot, it should be safe, but there is always a risk keeping anything in any kind of "plastic". I myself keep a bunch of glass jars in my pantry that I transfer lots of grains and pasta to so I can keep them out of plastic.

This is the same kind of plastic they use to store drinking water in, and it's common knowledge that if you leave water in your car and it gets hot, you're supposed to throw the water out because it leaches into the water.

I haven't been able to fight this fight yet. Right now all I can do is try to keep out BPA as much as possible by canning my own food (because BPA is in the linings of canned food, especially tomatoes.) I rarely use the microwave, and when I do I only use glass or ceramic. One of these days I'll be able to replace all my plastic storage containers to glass.