The present invention is for a pharmaceutical composition of lyophilized urate oxidase drug product with a diluent wherein the diluent comprises of propylene glycol and poloxamer 188 in the ratio of 9:1, which aggregate free, and physically stable solution after reconstitution. The diluent is a combination of GRAS listed Propylene Glycol and low amount of Polaxamer. After reconstitution of lyophilized powder of Urate Oxidase with the diluent provides an aggregate free, stable and active solution for at least 0-4h at 4�C or at 0-4h at 25�C.