Radiolysis of cyanocobalamin (vitamin B-12)

Research on the radiolysis of vitamins is of considerable interest since th ese compounds are important nutritional constituents in foods and in dietet ic supplements. In spite of these considerations there are few data and ver y often difficult to compare for the radiolytic behavior of vitamins. In th is work we focused our attention on to the study of the radiolysis of cyano cobalamin (vitamin B-12) in solid state and in aqueous solutions. The proce dure was followed by HPLC and UV-spectroscopy. The results obtained in aque ous solutions showed a dependence of the decomposition as a linear function of the dose. The G of decomposition for a 1 x 10(-5) M solution was 3.3. I n the solid state the vitamin was very stable towards the irradiation in th e conditions used in this study with a G = 2.1 x 10(-3). A study made with Serratia marcescens as a microbiological contaminant showed that at the ste rilization dose there is a destruction of the vitamin in aqueous solution. In the solid state the degree of decomposition was 7%. (C) 2000 Published b y Elsevier Science Ltd. All rights reserved.