<qa>  What is the polymeric NPs based on?Urea solution will be then prepared for eye drops purpose by enhancing its efficacy using the polymeric NPs based on the amphiphilic block copolymer PluronicF-127 PF which is an A-B-A-type triblock copolymer consisting of polyoxyethylene PEO units A and polyoxypropylene PPO units B with a thermoreversible gelation property that has a hydrophilic nontoxic property widely used as a pharmaceutical excipient for its stabilizing properties and capability to increase the solubility. 