◉ 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 possibly abnormal movements. One well-recognized at risk group 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.
Flash heat pasteurization of breastmilk does not reduce milk vitamin B12 concentration.
◉ 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.
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).
来源:Hazardous Substances Data Bank (HSDB)
毒理性
相互作用
患有恶性贫血的病人如果同时使用氯霉素，对维生素B12治疗的反应会很差。
Patients with pernicious anemia ... respond poorly to vitamin B12 therapy if chloroamphenicol is given concomitantly.
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.
Section 1. Chemical Product and Company Identification Methylcobalamin Catalog YY727, M1587 Common Name/ Number(s). Trade Name CAS# 13422-55-4 Manufacturer Commercial Name(s) Methylcobalamin Section 4. First Aid Measures Eye Contact Check for and remove any contact lenses. In case of contact, immediately flush eyes with plenty of water for at least 15 minutes. Cold water may be used. Get medical attention if irritation occurs. Skin Contact Wash with soap and water. Cover the irritated skin with an emollient. Get medical attention if irritation develops. Cold water may be used. Serious Skin Contact Not available. Inhalation If inhaled, remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical attention. Serious Inhalation Not available. Ingestion Do NOT induce vomiting unless directed to do so by medical personnel. Never give anything by mouth to an unconscious person. Loosen tight clothing such as a collar, tie, belt or waistband. Get medical attention if symptoms appear. Serious Ingestion Not available. Section 5. Fire and Explosion Data Flammability of the Product May be combustible at high temperature. Auto-Ignition Temperature Not available. Flash Points Not available. Flammable Limits Not available. These products are carbon oxides (CO, CO2), nitrogen oxides (NO, NO2...). Some metallic oxides. Products of Combustion Fire Hazards in Presence of Slightly flammable to flammable in presence of heat. Various Substances Non-flammable in presence of shocks. Explosion Hazards in Presence Risks of explosion of the product in presence of mechanical impact: Not available. of Various Substances Risks of explosion of the product in presence of static discharge: Not available. Fire Fighting Media SMALL FIRE: Use DRY chemical powder. and Instructions LARGE FIRE: Use water spray, fog or foam. Do not use water jet. Special Remarks on As with most organic solids, fire is possible at elevated temperatures Fire Hazards Special Remarks on Explosion Fine dust dispersed in air in sufficient concentrations, and in the presence of an ignition source is a potential dust Hazards explosion hazard. Section 6. Accidental Release Measures Small Spill Use appropriate tools to put the spilled solid in a convenient waste disposal container. Finish cleaning by spreading water on the contaminated surface and dispose of according to local and regional authority requirements. Large Spill Use a shovel to put the material into a convenient waste disposal container. Finish cleaning by spreading water on the contaminated surface and allow to evacuate through the sanitary system. Methylcobalamin Section 7. Handling and Storage Precautions Keep away from heat. Keep away from sources of ignition. Ground all equipment containing material. Do not ingest. Do not breathe dust. If ingested, seek medical advice immediately and show the container or the label. Keep away from incompatibles such as oxidizing agents. Storage Keep container tightly closed. Keep container in a cool, well-ventilated area. Do not store above 0°C (32°F). Freeze. Section 8. Exposure Controls/Personal Protection Engineering Controls Use process enclosures, local exhaust ventilation, or other engineering controls to keep airborne levels below recommended exposure limits. If user operations generate dust, fume or mist, use ventilation to keep exposure to airborne contaminants below the exposure limit. Personal Protection Safety glasses. Lab coat. Dust respirator. Be sure to use an approved/certified respirator or equivalent. Gloves. Personal Protection in Case of Splash goggles. Full suit. Dust respirator. Boots. Gloves. A self contained breathing apparatus should be used a Large Spill to avoid inhalation of the product. Suggested protective clothing might not be sufficient; consult a specialist BEFORE handling this product. Exposure Limits Not available. Section 9. Physical and Chemical Properties Physical state and appearance Solid. (Solidcrystalline powder.) Odor Odorless. Taste Not available. Molecular Weight 1344.4 g/mole Color Red. pH (1% soln/water) Not available. Not available. Boiling Point Melting Point Not available. Not available. Critical Temperature Specific Gravity Not available. Vapor Pressure Not applicable. Vapor Density Not available. Volatility Not available. Odor Threshold Not available. Water/Oil Dist. Coeff. Not available. Ionicity (in Water) Not available. Dispersion Properties See solubility in water. Solubility Partially soluble in cold water, hot water. Section 10. Stability and Reactivity Data The product is stable. Stability Instability Temperature Not available. Conditions of Instability Excess heat, dust generation, incompatibles. Reactive with oxidizing agents. Incompatibility with various substances Not available. Corrosivity Methylcobalamin Not available. Special Remarks on Reactivity Not available. Special Remarks on Corrosivity Polymerization Will not occur. Section 11. Toxicological Information Routes of Entry Inhalation. Ingestion. Toxicity to Animals Acute oral toxicity (LD50): 5000 mg/kg [Rat]. Chronic Effects on Humans Not available. Other Toxic Effects on Slightly hazardous in case of skin contact (irritant), of ingestion, of inhalation. Humans Special Remarks on Not available. Toxicity to Animals Special Remarks on May cause adverse reproductive and birth defects based on animal data. Chronic Effects on Humans May cause cancer (tumorigenic) based on animal data Special Remarks on other Acute Potential Health Effects: Toxic Effects on Humans Skin: May cause skin irritation. Eyes: Dust may cause eye irritation. Inhalation: Dust may cause respiratory tract irritation. Ingestion: May cause gastrointestinal tract irritation. Section 12. Ecological Information Ecotoxicity Not available. Not available. BOD5 and COD Possibly hazardous short term degradation products are not likely. However, long term degradation products may Products of Biodegradation arise. Toxicity of the Products The product itself and its products of degradation are not toxic. of Biodegradation Special Remarks on the Not available. Products of Biodegradation Section 13. Disposal Considerations Waste Disposal Waste must be disposed of in accordance with federal, state and local environmental control regulations. Section 14. Transport Information DOT Classification Not a DOT controlled material (United States). Not applicable. Identification Special Provisions for Not applicable. Transport Methylcobalamin DOT (Pictograms) Section 15. Other Regulatory Information and Pictograms No products were found. Federal and State Regulations California California prop. 65: This product contains the following ingredients for which the State of California has found to cause cancer which would require a warning under the statute: No products were found. Proposition 65 Warnings California prop. 65: This product contains the following ingredients for which the State of California has found to cause birth defects which would require a warning under the statute: No products were found. Other Regulations EINECS: This product is on the European Inventory of Existing Commercial Chemical Substances (EINECS No. 236-535-3). Canada: Not listed on Canadian Domestic Substance List (DSL) or Canadian Non-Domestic Substances List (NDSL). China: Not listed on National Inventory. Japan: Not listed on National Inventory (ENCS). Korea: Not listed on National Inventory (KECI). Philippines: Not listed on National Inventory (PICCS). Australia: Listed on AICS. WHMIS (Canada) Not controlled under WHMIS (Canada). Other Classifications DSCL (EEC) This product is not classified according Not applicable. to the EU regulations. Health Hazard HMIS (U.S.A.) 1 National Fire Protection 1 Flammability 1 Association (U.S.A.) Fire Hazard 1 0 Reactivity Health Reactivity 0 Specific hazard Personal Protection E WHMIS (Canada) (Pictograms) DSCL (Europe) (Pictograms) TDG (Canada) (Pictograms) ADR (Europe) (Pictograms) Protective Equipment Gloves. Methylcobalamin Lab coat. Dust respirator. Be sure to use an approved/certified respirator or equivalent.
