Codeine which was extracted from dry capsules of the opium poppy (Papaver somniferum) was purified by HPLC (High Performance Liquid Chromatography) and characterized by NMR (Nuclear Magnetic Resonance) and
IR (Infrared) spectroscopy techniques. The purified compound was labeled with 131I and biodistribution studies were performed in rats. Radioiodinated codeine distributed uniformly in the cerebellum, m.pons,
striatum and hypothalamus while the other branch of brain and Stomach, urinary bladder, and small intestine uptakes were significantly
higher than other tissues.