RESUMO
OBJECTIVE: To investigate the hygroscopicity of vitamin B12 and the related problems of its chemical reference substance (CRS) that should be paid attention to. METHODS: UV absorption coefficient was determined at 361 nm, using water as solvent. Dynamic vapor absorption analysis (DVS) was applied to evaluate the moisture sorption trend and capacities of vitamin B12 under different humilities. RESULTS: Owing to the strong hygroscopicity of vitamin B12, deviation in the process of weighing might result in smaller UV absorption coefficient compared with the actual value, especially for dried and low moisture content raw materials in high-humidity environment. CONCLUSION: In the study of drug quality control for vitamin B12, the strong hygroscopicity of the raw material should be paid attention to, particularly in the research and application of vitamin B12 CRS.