Cyanocobalamin
From Wikipedia, the free encyclopedia
| Cyanocobalamin | |
|---|---|
| Identifiers | |
| CAS number | 68-19-9 |
| PubChem | 16212801 |
| EC number | 200-680-0 |
| Properties | |
| Molecular formula | C63H88CoN14O14P |
| Molar mass | 1355.38 g/mol |
| Appearance | Dark red solid |
| Melting point | > 300 °C |
| Boiling point | > 300 °C |
| Solubility in water | Soluble |
| Hazards | |
| MSDS | External MSDS from Fisher Scientific |
| EU classification | Not available |
| S-phrases | S24/25 |
| NFPA 704 | 1 1 |
| Flash point | N/A |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) | |
| Infobox references | |
Cyanocobalamin is an especially common vitamer of the vitamin B12 family. It is the most famous vitamer of the family, because it is chemically the most air-stable, and it is the easiest to crystallize and therefore easiest to purify after it is produced by bacterial fermentation. A form of B12 called hydroxocobalamin is produced by bacteria, and then changed to cyanocobalamin in the process of being purified in activated charcoal columns after being separated from the bacterial cultures. Cyanide is naturally present in activated charcoal, and hydroxocobalamin, which has great affinity for cyanide, picks it up and is changed to cyanocobalamin. Thus, the cyanocobalamin form of B12 is the most widespread in the food industry.[1]
This fact has caused some people (usually from reading labels on packages and vitamin supplements, in which vitamin B12 is almost always listed last, since ingredients by law are listed in order of weight percentage), to infer that the correct chemical name of vitamin B12 actually is cyanocobalamin. In fact, vitamin B12 is the name for a whole class of chemicals with B12 activity, and cyanocobalamin is only one of these. Cyanocobalamin usually does not even occur in nature, and is not one of the forms of the vitamin which is directly used in the human body (or that of any other animal). However, animals and humans can convert cyanocobalamin to active (cofactor) forms of the vitamin, such as methylcobalamin.[1] This process happens by equilibration, as cyanocobalamin slowly loses its cyanide in surroundings that contain no cyanide.
Cyanide is present in cigarette smoke, and so there is some concern that B12 deficient smokers should not be given cyanocobalamin, as it will have more difficulty being broken down. In such cases, other forms of B12 for injection (such as hydroxocobalin itself) are commonly available as pharmaceuticals, and are actually the most commonly used injectable forms of B12 in many countries. Injectable cyanocobalamin remains the most commonly injectable B12 in the United States.
Contents |
Chemical Properties
Dark red crystals or an amorphous or crystalline red powder. Cyanocobalamin is very hygroscopic in the anhydrous form, and sparingly soluble in water (1:80). It is stable to autoclaving for short periods at 121°C. The vitamin B12 coenzymes are very unstable in light.
The chemical name is 5,6-dimethyl-benzimidazolyl cyanocobamide
Pharmaceutical Use
Cyanocobalamin is usually prescribed for the following reasons: after surgical removal of part, or all of the stomach or intestine to ensure there are adequate levels of vitamin B12 in the bloodstream; to treat pernicious anemia; vitamin B12 deficiency due to low intake from food; thyrotoxicosis, hemorrhage, malignancy, liver or kidney disease. Cyanocobamide is also used to perform the Schilling test to check your ability to absorb vitamin B12. [2]
Possible Side Effects
The oral use of cyanocobalamin may lead to several allergic reaction such as hives, difficult breathing, swelling of your face, lips, tongue, or throat. Less serious side effects may include headache, nausea, stomach upset, diarrhea, joint pain, itching, or rash. [3]
In the treatment of some forms of anemia (e.g. megaloblastic anemia), the use of cyanocobalamin can lead to severe hypokalemia, sometimes fatal, due to intracellular potassium shift upon anemia resolution. When treated with vitamin B12, patients with Leber's disease may suffer rapid optic atrophy.
References
- ^ a b Victor Herbert (1988). "Vitamin B-12: plant sources, requirements, and assay". American Journal of Clinical Nutrition 48 (3 Suppl): 852–8. PMID 3046314. http://www.ajcn.org/cgi/reprint/48/3/852.pdf.
- ^ http://www.umm.edu/altmed/drugs/cyanocobalamin-033700.htm
- ^ cyanocobalamin (oral), Cerner Multum, Inc. (Healthwise), 04/21/2009, http://health.msn.com/medications/articlepage.aspx?cp-documentid=100106512
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