Application: For the treatment of backache and ankylosing spondylitis. CAS Number: 50-33-9 IUPAC Name: 4-butyl-1,2-diphenyl-pyrazolidine-3,5-dione Molecular Formula: PBZ;Bute;Azdid;Butoz;Buzon;Kadol;Reudo;Uzone;A 7514;Azolid A drug that has anti-inflammatory, antipyretic, and analgesic.