Cobalamin metabolism and the clinical application in its different forms / 中华实用儿科临床杂志

ABSTRACT

Cobalamin, also known as Vitamin B 12, is the most complex vitamin in nature, and also one of essential vitamins in human body, which involved in many physiological activities, including homocysteine metabolism and translation of methylmalonyl-CoA to succinyl-CoA as a biological coenzyme.As a higher organism, human cannot synthesize cobalamin by themselves, so cobalamin needs to be supplemented by diet or medicine.At present, there are various forms of cobalamin, including cyanocobalamin (a common form of Vitamin B 12), hydroxylcobalamin, mecoba-lamin and 5′-adenosylcobalamin.These different forms of cobalamin are similar in structures and physiochemical pro-perties, but have some differences in the pharmacokinetics of absorption, distribution, metabolism and elimination, as well as clinical application and therapeutic efficacy.Among them, cyanocobalamin and hydroxycobalamin are widely used in Europe and the United States.Mecobalamin is more commonly used in Asia.5′-adenosylcobalamin has been approved in China, but less widely used in the world.Cyanocobalamin and mecobalamin are mainly used for the treatment of diseases caused by peripheral neuropathy and cobalamin deficiency.Hydroxycobalamin has been approved as an antidote to cyanide and has shown some potential in the treatment of methylmalonic acidemia in recent years.Now, the chemical structures, physiochemical properties, pharmacokinetic characteristics and clinical applications of the four cobalamins were compared and distinguished, so as to provide references for clinicians in clinical rational drug use and to avoid confusion.