Cyanocobalamin

Cyanocobalamin	Last updated: 05/09/2025
(Also known as: vitamin B12; anacobin)

GENERAL INFORMATION

Description

A human and veterinary drug used a vitamin supplement

Examples of veterinary uses

Substance used to treat cobalt deficiencies in livestock principally sheep

Examples of species treated

Sheep; Cattle; Horses; Pigs; Dogs; Cats

Approval status

VMR 2013/2033 approval status (GB/UK)

Approved - usually available as a prescription only medicine to be authorised by suitably qualified person (POM-VPS)

EU Regulatory approval status

Approved

Chemical structure

Isomerism

Cyanocobalamin exhibits stereoisomerism due to its highly complex and chiral structure. The molecule features a central cobalt ion coordinated within a corrin ring, which is similar to a porphyrin but more flexible. Around this macrocyclic ring are multiple chiral centres, specifically, nine carbon atoms on the periphery of the corrin system are stereogenic, meaning they can give rise to different spatial arrangements. Additionally, the cobalt ion is axially coordinated to two ligands: a cyano group and a nucleotide loop containing dimethylbenzimidazole, which further contributes to the molecule’s three-dimensional complexity. Although cyanocobalamin exists as a single stereoisomer in nature and pharmaceutical preparations, its structure allows for theoretical isomerism through variations in the configuration of these chiral centres and axial ligands.

Chemical formula

C₆₃H₈₈CoN₁₄O₁₄P

Canonical SMILES

CC1=CC2=C(C=C1C)N(C=N2)C3C(C(C(O3)CO)OP(=O)([O-])OC(C)CNC(=O)CCC4(C(C5C6(C(C(C(=C(C7=NC(=CC8=NC(=C(C4=N5)C)C(C8(C)C)CCC(=O)N)C(C7(C)CC(=O)N)CCC(=O)N)C)[N-]6)CCC(=O)N)(C)CC(=O)N)C)CC(=O)N)C)O.[C-]#N.[Co+3]

Isomeric SMILES

CC1=CC2=C(C=C1C)N(C=N2)[C@@H]3[C@@H]([C@@H]([C@H](O3)CO)OP(=O)([O-])O[C@H](C)CNC(=O)CC[C@@]4([C@H]([C@@H]5[C@]6([C@@]([C@@H](/C(=C(/C7=N/C(=C\C8=N/C(=C(\C4=N5)/C)/[C@H](C8(C)C)CCC(=O)N)/[C@H]([C@]7(C)CC(=O)N)CCC(=O)N)\C)/[N-]6)CCC(=O)N)(C)CC(=O)N)C)CC(=O)N)C)O.[C-]#N.[Co+3]

International Chemical Identifier key (InChIKey)

FDJOLVPMNUYSCM-WZHZPDAFSA-L

International Chemical Identifier (InChI)

InChI=1S/C62H88N13O14P.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;/h20-21,23,28,31,34-37,41,52-53,57,76,84H,12-19,22,24-27H2,1-11H3,(H2,63,77)(H2,64,78)(H2,65,79)(H2,66,80)(H2,67,81)(H2,68,82)(H,69,83)(H,85,86);;/q;;+1/p-1/b42-23-,54-32-,55-33-;;

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
cyanocobalamin hydrate	-

General status

Veterinary substance type

Medicinal drug

Substance groups

Unclassifed substance

Minimum active substance purity

Known relevant impurities

Substance origin

Natural

Mode of action

Converted to coenzyme B12 that is vital for a number of body processes including growth, hematopoiesis and nucleoprotein and myelin synthesis.

Molecular targets

[Methionine synthase], [Methylmalonyl-CoA mutase, mitochondrial], [Methionine synthase reductase, mitochondrial], [Methylmalonic aciduria type A protein, mitochondrial], [Methylmalonic aciduria and homocystinuria type C protein], [Amnionless protein], [Transcobalamin-1], [Transcobalamin-2], [Cob(I)yrinic acid a,c-diamide adenosyltransferase, mitochondrial], [Cubilin]

CAS RN

68-19-9

EC number

200-680-0

CIPAC number

US EPA chemical code

PubChem CID

166596686

Therapeutic Class

Blood & blood forming organs: Antianemic preparations

ATCvet Code

QB03BA01

Controlled Drug?

Regulation 37/2010 MRL Classification

Not applicable - vitamin

Molecular mass

1355.38

PIN (Preferred Identification Name)

IUPAC name

5,6-dimethylbenzimidazolylcobamide cyanide

CAS name

5,6-dimethyl-benzimidazolyl cyanocobamide

Forever chemical

Other status information

Relevant Environmental Water Quality Standards

Physical state

Dark red to brown hygroscopic crystalline solid

Commercial

Property

Value

Availability status

Current

Introduction & key dates

1955, introduced

Example manufacturers & suppliers of products using this active now or historically

Interchemie Werken De Adelaar Eesti AS
Livisto International SA
Alfasan Nederland B.V.

Example products using this active

Butasal Solution for injection
Vigophos Solution for Injection
Vitbee Solution for injection

Formulation and application details

Usually supplied as a solution for injection

Commercial production

Cyanocobalamin is produced through a microbial fermentation process using specialized bacteria such as Propionibacterium freudenreichii or Pseudomonas denitrificans. These microbes are cultivated in nutrient-rich media containing carbon sources, nitrogen, cobalt, and precursors like dimethylbenzimidazole, which are essential for assembling the complex corrin ring structure of cobalamin. During fermentation, the bacteria primarily synthesise hydroxocobalamin or other cobalamin derivatives. After fermentation, the broth is processed to extract and purify the vitamin using adsorption and ion-exchange chromatography. A final cyanation step chemically converts the purified cobalamin into cyanocobalamin by attaching a cyanide group to the cobalt centre.

Impact on climate of production and use

As microbial-based products tend to use fermentation-based production processes rather than chemical synthesis, they typically have a lower fossil fuel input in formulation and active ingredient creation, and also have reduced downstream emissions due to biodegradability and minimal soil disruption, their life-cycle GHG emissions are expected to be low. Whilst hard and precise data is not available, some broad estimates suggest that typically emissions are likely to be below 5 kg CO₂e/kg of substance.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

Solubility - In water at 20 °C (mg l⁻¹)

12500

High

Solubility - In organic solvents at 20 °C (mg l⁻¹)

Melting point (°C)

102.5

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

Flashpoint (°C)

Octanol-water partition coefficient at pH 7, 20 °C

3.72 X 10⁰³

Calculated

Log P

3.57

High

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

Henry's law constant at 25 °C (Pa m³ mol⁻¹)

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

Maximum UV-vis absorption L mol⁻¹ cm⁻¹

In water max at: 278nm, 361nm & 55nm

Surface tension (mN m⁻¹)

Refractive Index

Environmental release

Degradation

Property

Value

Source; quality score; and other information

Interpretation

Soil degradation (days) (aerobic)

DT₅₀ (typical)

DT₅₀ (lab at 20 °C)

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

Note

Manure DT₅₀ (days)

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Note

Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7

Value

Note

Water-sediment DT₅₀ (days)

Water phase only DT₅₀ (days)

Sediment phase only DT₅₀ (days)

Air degradation

As this parameter is not normally measured directly, a surrogate measure is used: ‘Photochemical oxidative DT₅₀’. Where data is available, this can be found in the Fate Indices section below.

Decay in stored produce DT₅₀

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d (mL g⁻¹)

K_oc (mL g⁻¹)

Notes and range

Freundlich

K_f (mL g⁻¹)

K_foc (mL g⁻¹)

¹/_n

Notes and range

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

Bio-concentration factor

BCF (l kg⁻¹)

CT₅₀ (days)

Known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 5000

Mouse

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

(ppm diet)

Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)

Birds - Acute LD₅₀ (mg kg⁻¹)

Birds - Short term dietary (LC₅₀/LD₅₀)

Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)

Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)

Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)

Soil micro-organisms

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Non-target plants

Vegetative vigour ER₅₀ (g ha⁻¹)

Seedling emergence ER₅₀ (g ha⁻¹)

Honeybees (Apis spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Chronic

Notes

Bumblebees (Bombus spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Mason bees (Osmia spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Other bee species (1)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Other bee species (2)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Beneficial insects (Ladybirds)

Beneficial insects (Lacewings)

Beneficial insects (Parasitic wasps)

Beneficial insects (Predatory mites)

Beneficial insects (Ground beetles)

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)

Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)

Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)

Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)

Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)

Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)

Aquatic Plants (free-floating, fonds growth, fresh) - 7 day (mg l⁻¹)

Aquatic plants (rooted, growth rate, fresh) - 14 day (mg l⁻¹)

Algae - Acute (growth rate, fresh; mg l⁻¹)

Algae - Chronic (growth rate, fresh; mg l⁻¹)

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves

HUMAN HEALTH AND PROTECTION

General

Property

Value

Source; quality score; and other information

Interpretation

Threshold of Toxicological Concern (Cramer Class)

High (class III)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 5000

Mouse

Low

Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)

Mammals - Inhalation LC₅₀ (mg l⁻¹)

Other Mammal toxicity endpoints

Intraperitoneal LDLo = 1.36 mg kg⁻¹

Mouse

Intravenous LD₅₀ > 2000 mg kg⁻¹

Mouse

ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)

ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)

AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)

AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

Public

Occupational

Mammalian dose elimination route and rate

Rapidly excreted in the urine and faeces but also identified in human breast milk and bile

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

No data found

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

Generally considered to be non-toxic
May lead to allergic reactions
May cause breathing difficulties

Handling issues

Property

Value and interpretation

General

Use water spray, fog or foam to fight fires. Do not use water jet

CLP classification 2013

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

cyanocobalamin

French

cyanocobalamine

German

Danish

Italian

Spanish

cianocobalamina

Greek

Polish

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	05/09/2025
Contact:	aeru@herts.ac.uk
Please cite as:	Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242