Cyanocobalamin   中文名称: 维生素B12

在所有 B 族维生素中，维生素 B12 是其中之一。大多数情况下，它影响DNA的合成和调节，但它也在能量产生、脂肪酸合成（特别是奇数链脂肪酸合成）以及人体内每个细胞的新陈代谢中发挥作用。然而，由于身体再次产生叶酸需要维生素 B12，因此足够量的叶酸（维生素 B9）可以替代维生素 B12 的许多（如果不是全部）作用。当身体因甲基捕获而缺乏足够的叶酸来产生胸腺嘧啶时，DNA 的合成就会发生不良。因此，大多数与维生素 B12 缺乏相关的症状实际上是叶酸缺乏的症状。这包括巨幼细胞增多症和恶性贫血的所有影响。当获得足够的叶酸时，所有已知的维生素 B12 相关缺乏综合症都会恢复正常，但与各自底物同型半胱氨酸和甲基丙二酸以及维生素 B12 依赖性酶甲基丙二酰辅酶 A 变位酶的生长具体相关的综合症除外和 5-甲基四氢叶酸-同型半胱氨酸甲基转移酶 (MTR)，也称为蛋氨酸合酶。辅酶 B12 中的反应性 C-Co 键有助于三大类酶催化反应[1][2]。

Absorption, Distribution and Excretion
Vitamin B12 is quickly absorbed from intramuscular (IM) and subcutaneous (SC) sites of injection; with peak plasma concentrations achieved about 1 hour after IM injection. Orally administered vitamin B12 binds to intrinsic factor (IF) during its transport through the stomach. The separation of Vitamin B12 and IF occurs in the terminal ileum when calcium is present, and vitamin B12 is then absorbed into the gastrointestinal mucosal cells. It is then transported by transcobalamin binding proteins. Passive diffusion through the intestinal wall can occur, however, high doses of vitamin B12 are required in this case (i.e. >1 mg). After the administration of oral doses less than 3 mcg, peak plasma concentrations are not reached for 8 to 12 hours, because the vitamin is temporarily retained in the wall of the lower ileum.
This drug is partially excreted in the urine. According to a clinical study, approximately 3-8 mcg of vitamin B12 is secreted into the gastrointestinal tract daily via the bile. In patients with adequate levels of intrinsic factor, all except approximately 1 mcg is reabsorbed. When vitamin B12 is administered in higher doses that saturate the binding capacity of plasma proteins and the liver, the unbound vitamin B12 is eliminated rapidly in the urine. The body storage of vitamin B12 is dose-dependent.
Cobalamin is distributed to tissues and stored mainly in the liver and bone marrow.
During vitamin loading, the kidney accumulates large amounts of unbound vitamin B12. This drug is cleared partially by the kidney, however, multiligand receptor _megalin_ promotes the reuptake and reabsorption of vitamin B12 into the body,.
IN MICE INJECTED IV WITH VITAMIN B12, THE VITAMIN ACCUMULATED RAPIDLY IN THE PLACENTA & WAS TRANSFERRED SLOWLY TO THE FETUSES. PEAK CONCN IN THE FETUSES WAS REACHED 24 HR AFTER DOSING, & FETAL ACCUMULATION WAS DOSE-DEPENDENT.
IN /MICE/ VITAMIN B12 PRESENTS UNUSUAL PATTERN OF PLACENTAL TRANSFER, FOR EVEN WITH 0.20 UG MATERNAL DOSE AVG FETAL CONCN IS 130 TIMES HIGHER THAN MATERNAL ONE. THIS INDICATES STRONGLY OPERATION OF SPECIFIC TRANSPORT MECHANISM FOR VITAMIN B12, POSSIBLY SIMILAR TO ITS GI ABSORPTION ...
IN RATS, PLACENTAL TRANSFER OF VITAMIN B12 WAS SHOWN TO INCR DURING GESTATION. ALTHOUGH QUANTITY TRANSPORTED EACH DAY WAS PROPORTIONAL TO FETAL WT, THE AMT TRANSPORTED PER G OF PLACENTA INCR TEN-FOLD FROM DAY 10 TO DAY 19.
Vitamin B12 is irregularly absorbed from the distal small intestine following oral administration. Dietary vitamin B12 is protein bound and this bond must be split by proteolysis and gastric acid before absorption. In the stomach, free vitamin B12 is attached to intrinsic factor; intrinsic factor a glycoprotein secreted by the gastric mucosa, is necessary for active absorption of the vitamin from the GI tract. The vitamin B12-intrinsic factor complex passes into the intestine, where much of the complex is transiently retained at specific receptor sites in the wall of the lower ileum before the vitamin B12 portion is absorbed into systemic circulation.
For more Absorption, Distribution and Excretion (Complete) data for CYANOCOBALAMIN (9 total), please visit the HSDB record page.

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Metabolism / Metabolites
Vitamin B12 or cyanocobalamin obtained from food is initially bound by _haptocorrin_, a protein found in the saliva with high affinity for B12. This forms a _haptocorrin-B12_ complex. Cyanocobalamin passes through the stomach and is protected from acid degradation due to its binding to haptocorrin. In the duodenum, pancreatic _proteases_ release cobalamin from the _haptocorrin-B12 complex_ and from other proteins containing protein-bound B12 that have been ingested. Following this, the binding of cobalamin to a second glycoprotein, _intrinsic factor_, promotes its uptake by terminal ileum mucosal cells by a process called _cubilin_/AMN receptor-mediated endocytosis. After absorption into enterocytes, intrinsic factor is broken down in the lysosome, and cobalamin is then released into the bloodstream. The transporter ABCC1, found in the basolateral membrane of intestinal epithelial and other cells, exports cobalamin bound to transcobalamin out of the cell. Cyanocobalamin then passes through the portal vein in the liver, and then reaches the systemic circulation. The active forms of cyanocobalamin are _methylcobalamin_ and _adenosylcobalamin_,.
Vitamin B12 is believed to be converted to coenzyme form in the liver and is probably stored in tissues in this form.
Intracellular vitamin B12 is maintained as two active coenzymes methylcobalamin and deoxyadenasylcobalamin.

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Biological Half-Life
Approximately 6 days (400 days in the liver).
HALF-LIFE OF IV ADMIN CYANOCOBALAMIN IN SERUM IS ABOUT 6 DAYS.

Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
Vitamin B12 is a normal component of human milk. The recommended daily intake in lactating women is 2.8 mcg and for infants aged 6 months or less is 0.4 mcg. Some authorities recommend 5.5 mcg per day during lactation. Supplementation may be necessary to achieve these recommended daily intakes or to correct a known deficiency. Low doses (1 to 10 mcg) of vitamin B12 found in B complex or prenatal vitamins increase milk levels only slightly. Higher daily doses of 50 to 250 mcg are needed in cases of maternal deficiency. The breastfed infant is not exposed to excessive vitamin B12 in such cases, and their vitamin B12 status should improve if it was previously inadequate.
Poor health outcomes in infants with vitamin B12 deficiency include anemia, abnormal skin and hair development, convulsions, weak muscle tone, failure to thrive, mental developmental delay, and potentially abnormal movements. Well-recognized at risk groups are exclusively breastfed infants of mothers with B12 deficiency due to minimal or no dietary intake of animal products or pernicious anemia caused by a maternal malabsorption of B12. Infant vitamin B12 status can be improved through maternal B12 supplementation during pregnancy and lactation. Deficient mothers who miss the opportunity to supplement during pregnancy should still be encouraged to supplement during early lactation since infant vitamin B12 status correlates with milk vitamin B12 levels in breastfed infants up to 6 months of age. Although there are cases reported of exclusively breastfed infants with vitamin B12 deficiency having biochemical and clinical improvement through adequate maternal supplementation alone, direct supplementation of the infant is recommended when such treatments are available.
◉ Effects in Breastfed Infants
Twelve exclusively breastfed infants between 4 and 11 months of age had biochemical, hematological and clinical findings consistent with vitamin B12 deficiency. Their mothers received a 50 mcg single dose of intramuscular vitamin B12. Within 5 to 8 days after the dose, the infants experienced significantly increased hemoglobin and reticulocyte counts, normoblastic erythropoiesis, improved mental status, regression of abnormal skin pigmentation, and reduction in tremors.
Three hundred sixty-six pregnant women in India received 50 mcg of oral vitamin B12 or placebo capsules once daily beginning during their first trimester of pregnancy and continuing until 6 weeks postpartum. Among 218 infants that underwent neurodevelopment testing at 30 months of age, those born to mothers randomized to vitamin B12 had higher expressive language scores than the placebo group when adjusted for baseline maternal vitamin B12 deficiency. Cognitive, receptive language and motor scores were not different between the two groups. Neurophysiological assessments were then conducted at 6 years of age and there were no differences in the measured brain activity between the two groups.
◉ Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.

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Protein Binding
Very high (to specific plasma proteins called transcobalamins); binding of hydroxocobalamin is slightly higher than cyanocobalamin [FDA label.

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Interactions
ABSORPTION OF VITAMINE B12 FROM THE GI TRACT MAY BE DECR BY AMINOGLYCOSIDE ANTIBIOTICS, COLCHICINE, EXTENTED-RELEASE POTASSIUM PREPN, AMINOSALICYLIC ACID & ITS SALTS, ANTICONVULSANTS (EG, PHENYTOIN, PHENOBARBITAL, PRIMADONE), COBALT IRRADIATION OF THE SMALL BOWEL, & BY EXCESSIVE ALCOHOL INTAKE LASTING LONGER THAN 2 WK.
The gastrointestinal absorption of vitamin B12 can be considerably decreased by oral neomycin. Colchicine administration appears to increase neomycin-induced malabsorption of vitamin B12.
The decreased vitamin B12 absorption induced by aminosalicylic acid may be due to the mild malabsorption syndrome that occurs in some patients treated with aminosalicylic acid (PAS).
Patients with pernicious anemia ... respond poorly to vitamin B12 therapy if chloroamphenicol is given concomitantly.
For more Interactions (Complete) data for CYANOCOBALAMIN (7 total), please visit the HSDB record page.

[1]. http://en.wikipedia.org/wiki/Vitamin_B12
[2]. Banerjee, R. and S.W. Ragsdale, The many faces of vitamin B12: catalysis by cobalamin-dependent enzymes. Annu Rev Biochem, 2003. 72: p. 209-47.

Therapeutic Uses
Hematinics
Vitamin B12 is used in the treatment of pernicious anemia and other vitamin B12 deficiency states. ... Cyanocobalamin ... usually indicated in patients with malabsorption of vitamin B12, such as those with tropical or nontropical sprue (idiopathic steatorrhea, gluten-induced enteropathy); partial or total gastrectomy; regional enteritis; gastroenterostomy; ileal resection; or malignancies, granulomas, strictures, or anastomoses involving the ileum. When the secretion of intrinsic factor is decreased by lesions that destroy the gastric mucosa (eg, following ingestion of corrosives or in patients with extensive GI neoplasia) or by gastric atrophy secondary to multiple sclerosis, certain endocrine disorders, or iron deficiency, or when antibodies to intrinsic factor are present in gastric juice, absorption of vitamin B12 is decreased and cyanocobalamin ... may be required. Malabsorption of vitamin B12 may also be caused by competition for vitamin B12 by bacteria (blind loop syndrome) or by fish tapeworm, Diphyllobothrium latum, or by admin of certain drugs.
The individual with an uncomplicated pernicious anemia, in which the abnormality is restricted to a mild or moderate anemia ... will respond quite well to the admin of vitamin B12 alone.
... Patients with neurological change or severe leukopenia or thrombocytopenia associated with infection or bleeding require emergency treatment. The older individual with a severe anemia (hematocrit less than 20%) is likely to have tissue hypoxia, cerebrovascular insufficiency, and congestive heart failure. Effective therapy must not wait for detailed diagnostic tests. ... The patient should receive intramuscular injections of 100 ug of cyanocobalamin and 1 to 5 mg of folic acid.
For more Therapeutic Uses (Complete) data for CYANOCOBALAMIN (13 total), please visit the HSDB record page.

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Drug Warnings
Cyanocobalamin injection is extremely safe when given by the intramuscular or deep subcutaneous route, but it should never be given intravenously.
Cyanocobalamin should not be used in patients with early Leber's disease (hereditary optic nerve atrophy), since rapid optic nerve atrophy has been reported following admin of the drug to these patients. Vitamin B12 is contraindicated in patients who have experienced hypersensitivity reactions to the vitamin or to cobalt.
/"SHOTGUN"/ ... VITAMIN THERAPY IN TREATMENT OF ... DEFICIENCY CAN BE DANGEROUS. ... THERE IS DANGER THAT SUFFICIENT FOLIC ACID WILL BE GIVEN TO RESULT IN HEMATOLOGICAL RECOVERY; HOWEVER, THIS MAY MASK CONTINUED VIT-B DEFICIENCY & NEUROLOGICAL DAMAGE WILL DEVELOP OR PROGRESS IF ALREADY PRESENT.
Maternal Medication usually Compatible with Breast-Feeding: B12: Reported Sign or Symptom in Infant or Effect on Lactation: None. /from Table 6/
Serum potassium concn should be monitored during early vitamin B12 therapy & potassium admin is necessary, since fatal hypokalemia could occur upon conversion of megaloblastic anemia to normal erythropoesis with vitamin B12 as a result of increased erythrocyte potassium requirements. Because vitamin B12 deficiency may suppress the signs of polycythemia vera, treatment with cyanocobalamin may unmask this condition. The increase in nucleic acid degradation produced by admin vitamin B12 to vitamin B12- deficient patients could result in gout in susceptible individuals. Therapeutic response to vitamin B12 may be impaired by concurrent infection, uremia, folic acid or iron deficiency, or by drugs having bone marrow suppressant effects. Folic acid should be admin with extreme caution to patients with undiagnosed anemia, since folic acid may obscure the diagnosis of pernicious anemia by alleviating hematologic manifestations of the disease while allowing neurologic complications to progress. This may result in severe nervous system damage before the correct diagnosis is made. Vitamin preparations containing folic acid should be avoided by patients with pernicious anemia because folic acid may actually potentiate neurologic complications of vitamin B12 deficiency. Conversely, doses of cyanocobalamin exceeding 10 micrograms daily may improve folate-deficient megaloblastic anemia and obscure the true diagnosis.

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Pharmacodynamics
**General effects** Cyanocobalamin corrects vitamin B12 deficiency and improves the symptoms and laboratory abnormalities associated with pernicious anemia (megaloblastic indices, gastrointestinal lesions, and neurologic damage). This drug aids in growth, cell reproduction, hematopoiesis, nucleoprotein, and myelin synthesis. It also plays an important role in fat metabolism, carbohydrate metabolism, as well as protein synthesis. Cells that undergo rapid division (for example, epithelial cells, bone marrow, and myeloid cells) have a high demand for vitamin B12. **Parenteral cyanocobalamin effects** The parenteral administration of vitamin B12 rapidly and completely reverses the megaloblastic anemia and gastrointestinal symptoms of vitamin B12 deficiency. Rapid parenteral administration of vitamin B12 in deficiency related neurological damage prevents the progression of this condition. **Nasal spray effects** In 24 vitamin B12 deficient patients who were already stabilized on intramuscular (IM) vitamin B12 therapy, single daily doses of intranasal cyanocobalamin for 8 weeks lead to serum vitamin B12 concentrations that were within the target therapeutic range (>200 ng/L).

C63H92CON14O14P

1359.41

1354.567

68-19-9

5311498

Dark red crystals or an amorphous or crystalline red powder
Dark-red crystals or red powder

>300ºC

6.57

479.7

9

21

26

93

3220

14

[Co+2].P(=O)(O[H])(O[C@]1([H])[C@@]([H])(C([H])([H])O[H])O[C@@]([H])([C@]1([H])O[H])N1C([H])=NC2C([H])=C(C([H])([H])[H])C(C([H])([H])[H])=C([H])C1=2)OC([H])(C([H])([H])[H])C([H])([H])N([H])C(C([H])([H])C([H])([H])[C@@]1(C([H])([H])[H])C2C(C([H])([H])[H])=C3[C@@]([H])(C([H])([H])C([H])([H])C(N([H])[H])=O)C(C([H])([H])[H])(C([H])([H])[H])C(C([H])=C4[C@@]([H])(C([H])([H])C([H])([H])C(N([H])[H])=O)[C@](C([H])([H])[H])(C([H])([H])C(N([H])[H])=O)C(C(C([H])([H])[H])=C5[C@@]([H])(C([H])([H])C([H])([H])C(N([H])[H])=O)[C@](C([H])([H])[H])(C([H])([H])C(N([H])[H])=O)[C@](C([H])([H])[H])([C@@]([H])([C@]1([H])C([H])([H])C(N([H])[H])=O)N=2)[N-]5)=N4)=N3)=O.[C-]([H])([H])[H] |t:73,99,132|

FDJOLVPMNUYSCM-WZHZPDAFSA-L

InChI=1S/C62H90N13O14P.CN.Co/c1-29-20-39-40(21-30(29)2)75(28-70-39)57-52(84)53(41(27-76)87-57)89-90(85,86)88-31(3)26-69-49(83)18-19-59(8)37(22-46(66)80)56-62(11)61(10,25-48(68)82)36(14-17-45(65)79)51(74-62)33(5)55-60(9,24-47(67)81)34(12-15-43(63)77)38(71-55)23-42-58(6,7)35(13-16-44(64)78)50(72-42)32(4)54(59)73-56;1-2;/h20-21,23,28,31,34-37,41,52-53,56-57,76,84H,12-19,22,24-27H2,1-11H3,(H15,63,64,65,66,67,68,69,71,72,73,74,77,78,79,80,81,82,83,85,86);;/q;-1;+3/p-2/t31-,34-,35-,36-,37+,41-,52-,53-,56-,57+,59-,60+,61+,62+;;/m1../s1

cobalt(3+);[(2R,3S,4R,5S)-5-(5,6-dimethylbenzimidazol-1-yl)-4-hydroxy-2-(hydroxymethyl)oxolan-3-yl] [(2R)-1-[3-[(1R,2R,3R,5Z,7S,10Z,12S,13S,15Z,17S,18S,19R)-2,13,18-tris(2-amino-2-oxoethyl)-7,12,17-tris(3-amino-3-oxopropyl)-3,5,8,8,13,15,18,19-octamethyl-2,7,12,17-tetrahydro-1H-corrin-24-id-3-yl]propanoylamino]propan-2-yl] phosphate;cyanide

Docigram Vitamin B12 Cyanocobalamin

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

注意： 本产品在运输和储存过程中需避光。

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~20.83 mg/mL (~14.14 mM)
H2O : ~6.25 mg/mL (~4.24 mM)

配方 1 中的溶解度: ≥ 2.5 mg/mL (1.70 mM) (饱和度未知) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，可将100 μL 25.0 mg/mL澄清DMSO储备液加入到400 μL PEG300中，混匀；然后向上述溶液中加入50 μL Tween-80，混匀；加入450 μL生理盐水定容至1 mL。
*生理盐水的制备：将 0.9 g 氯化钠溶解在 100 mL ddH₂O中，得到澄清溶液。

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配方 2 中的溶解度: ≥ 2.5 mg/mL (1.70 mM) (饱和度未知) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，可将 100 μL 25.0 mg/mL澄清DMSO储备液加入900 μL 20% SBE-β-CD生理盐水溶液中，混匀。
*20% SBE-β-CD 生理盐水溶液的制备（4°C，1 周）：将 2 g SBE-β-CD 溶解于 10 mL 生理盐水中，得到澄清溶液。

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配方 3 中的溶解度: 50 mg/mL (33.94 mM) in PBS (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液; 超声助溶.

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请根据您的实验动物和给药方式选择适当的溶解配方/方案：
1、请先配制澄清的储备液(如：用DMSO配置50 或 100 mg/mL母液(储备液));
2、取适量母液，按从左到右的顺序依次添加助溶剂，澄清后再加入下一助溶剂。以 下列配方为例说明 (注意此配方只用于说明，并不一定代表此产品 的实际溶解配方):
10% DMSO → 40% PEG300 → 5% Tween-80 → 45% ddH2O (或 saline);
假设最终工作液的体积为 1 mL, 浓度为5 mg/mL: 取 100 μL 50 mg/mL 的澄清 DMSO 储备液加到 400 μL PEG300 中，混合均匀/澄清；向上述体系中加入50 μL Tween-80，混合均匀/澄清；然后继续加入450 μL ddH2O (或 saline)定容至 1 mL；
3、溶剂前显示的百分比是指该溶剂在最终溶液/工作液中的体积所占比例;
4、 如产品在配制过程中出现沉淀/析出，可通过加热(≤50℃)或超声的方式助溶;
5、为保证最佳实验结果，工作液请现配现用！
6、如不确定怎么将母液配置成体内动物实验的工作液，请查看说明书或联系我们;
7、 以上所有助溶剂都可在 Invivochem.cn网站购买。