Need help on how to remove dresser drawers!

I'm guessing these shattered because of shock or perhaps from being fully extended more than normal since the front wheel takes a lot of the weight when drawer is fully extended. The rail is acting as a lever where 10kg in the front of the drawer could easily be the equivalent of 100kg on that wheel when the drawer is fully open. The other thoughts are if someone where to lean on the drawer or if the cabinet was being moved and dropped.

I've seen replacement wheels, but they tend to be for specific rails/sliders, and I doubt you'd get a good result without a perfect match. For replacing the entire slider, I'd look for a replacement with a high weight limit. I've seen sliders in the US that are designed for 50kg, which I'm guessing would more than handle your load.

It means the slide is 16" long and that you can pull your drawer out a full 16" relative to the slide. If your cabinet space was 20" deep, and you mounted this all the way at the back then your drawer would not come out 16" but instead 16-4=12".