The present invention relates to methods for making oxidation resistant homogenized polymeric materials and medical implants that comprise polymeric materials, for example, ultra-high molecular weight polyethylene (UHMWPE). The invention also provides methods of making antioxidant-doped medical implants, for example, doping of medical devices containing cross-linked UHMWPE with vitamin E by diffusion and annealing the antioxidant doped UHMWPE in a super critical fluid, and materials used therein.