Polymeric nanoparticles with a hydrophobic core and a hydrophilic shell are formed from: 1) N-isopropylacrylamide (NIPAAM), at a molar ratio of about 50% to about 90%, and preferably 60% for specific delivery routes such as oral or parenteral； either water-soluble vinyl derivatives like vinylpryolidone (VP) or vinyl acetate (VA), or water insoluble vinyl derivaties like methyl methacrylate (MMA) or styrene (ST), at a molar ratio of about 10% to about 30%； and acrylic acid (AA), at a molar ration of about 10% to about 30%.
