Febuxostat 144060-53-7 C16H16N2O3S white crystalline powder; ; 99.9% . antipodagric Benzbromarone 3562-84-3 C17H12Br2O3 Probenecid 5 7-66-9 C13H19NO4S White or almost white crystalline powder; 98.5% ( + / -) -Sulfinpyrazone 57-96-5 C23H20N2O3S Allopurinol 315-30-0 C5H4N4O white powder; loss on drying