Pyridoxine (B₆)

Abstract

Vitamins (Pyridoxine–B 6 ) . Burdick, David (Hoffmann‐La Roche Inc.). Vitamin B 6 consists of a group of six biochemically interconvertible substances, pyridoxine, pyridoxol, pyridoxamine, and their 5′‐phosphates. These are found in the tissues and fluids of virtually all living organisms. Pyridoxal phosphate plays essential roles in over 100 enzymes involved with amino acid biochemistry. Humans and animals cannot biosynthesize vitamin B 6 and require it in their diets or in supplements to prevent a number of metabolic and neural disorders. Humans require 2 mg/d in their diets. Chemical interactions with some food and drug components can reduce bioavailability of vitamin B 6 . Pyridoxine is the most stable of the B 6 vitamers. It is quite stable when dry or in acidic solution but degrades with base or irradiation. Production from natural sources or bioprocesses is not practical. All of the more than 3000 t/yr world production is made by chemical synthesis by variants of a cycloaddition route of substituted oxazoles with butenediol derivatives. Pyridoxine hydrochloride is widely used in foods, feeds, and multivitamin supplements. Essentials of the history, occurrence, biosynthesis, biochemical and physiological functions, chemical transformations, manufacturing chemistry, analytical methods, safety and handling, product forms, and uses of vitamin B 6 are briefly reviewed.