White powder separating out of methadone drinks?

I get methadone drinks (Methadone solution in orange sugar-free drink) but when I take my drinks out of the fridge, there's always a bunch of white powder separated out in the bottom of the bottles...

Just wondering if anyone knows whether that's methadone powder or what the hell is happening?

edit : I think I answered my own question... I tasted a bit of the residue of that white powder and it's not bitter, and tastes like nothing. I don't know what it is, but it's probably not methadone powder.