It is my understanding that the Gillette Platinum blades in the blue box are no longer being made, but I may be mistaken. I do have some in my den, however. I find the Gillette Platinum blades to be very similar to the Gillette Silver Blue blades. Some have suggested that the Platinum and GSB blades may be the same blade in an updated package. I find them both to be sharper than the Rubies I have tried, but YMMV.
Maybe you are referring to these:
GSBs are Teflon coated, the Gillette Platinums are platinum coated.