[...] Still as others have stated, the filler may not even be what is causing your throat burn.
Quick way to find out: Remove the filler from a cart, drip 2 drops onto the atomizer, replace the (empty) cart, and vape. You'll get a few mediocre vapes, then one or two really good vapes, then the
flavor will diminish (and the
vapor may actually increase slightly), just before the atty is dry. When you get a burnt taste, the atty is dry. That's not good for the atty, and it tastes bad. You quickly get to know when the atomizer needs another 2 drops, so you can avoid letting it go dry.
That's called "dripping", and that's what I do almost exclusively (hate fiddling around with carts). If it's still giving you the burning sensation in your throat, then the problem isn't with the filler, because you're getting nothing but vape (unless it's a new atomizer and you didn't get all of the shipping fluid out of it).
CAUTION: If you're using a non-sealed automatic battery (no button), and you drip way too much juice, the juice can leak into the battery through the hole in the atomizer, and ruin the battery or the switch.