Cobalamins and Methylcobalamin: Coenzyme of Vitamin B12
Şeyda AKKUŞ ARSLAN*°, İsmail ARSLAN**, Figen TIRNAKSIZ*

* Gazi University, Faculty of Pharmacy, Dept. Pharmaceutical Technology, 06330, Ankara, TURKEY.
** Ankara Training and Research Hospital, Department of Family Medicine, 06230, Ankara-TURKEY.
°Corresponding Author :
Phone: +90 (312) 202 30 40/54
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SUMMARY
Vitamin B12, also called cobalamin, is one of the B vitamins. Cobalamin may refer to several chemical forms of vitamin B12, depending on the ligand of the cobalt ion. These are cyanocobalamin, hydroxycobalamin, methylcobalamin and
adenosylcobalamin. For many years preparations of vitamin B12 (cobalamin) have been finding use in medicine. All of the forms of cobalamin are present in substantial amounts in the human and animal organism. Cobalamin plays a specific role in amino acid metabolism, i.e. in the methionine synthase reaction. Crystalline cobalamins are administered parenterally (intramuscularly) or orally (except hydroxycobalamin) for treating deficiency states. The absorption of physiological doses of cobalamin is limited to approximately 1.5 – 2 μg/dose. Methylcobalamin is one of the two coenzyme forms of cobalamin. It is the metabolically active form required for cobalamin-dependent enzyme function. Intramuscular administration is widely accepted as a treatment method. Oral cobalamin supplementation is also used but it is considered to be less reliable. Therefore, a nanoemulsion formulation was developed to overcome this problem by the authors. In this review, especially the general information about cobalamin and methylcobalamin will be shared. Besides, information about the developed nanoemulsion will be given.

Key Words: Cobalamin, methylcobalamin, vitamin B12.