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Milbemycin oxime (Ref: CGA-179246)
Last updated: 14/01/2024
(Also known as: Milbemycin-A4-oxim )
GENERAL INFORMATION
Description
A broad-spectrum antiparasitic drug producted by the fermentation by Streptomyces hygroscopicus variant aureolacrimosus
Availability status
Current
Introduction & key dates
circa 1972, introduced
Examples of veterinary uses
Used for the treatment of heartworms, mites, fleas, ticks and nematodes (roundworms, tapeworms, hookworms)
Examples of species treated
Dogs; Cats
Approval status
VMR 2013/2033 approval status (GB/UK)
Approved
EU Regulatory approval status
Approved
Chemical structure
Isomerism
Isomeric
Chemical formula
C₆₃H₈₈N₂O₁₄
Canonical SMILES
CCC1C(CCC2(O1)CC3CC(O2)CC=C(CC(C=CC=C4COC5C4(C(C=C(C5=NO)C)C(=O)O3)O)C)C)C.CC1CCC2(CC3CC(O2)CC=C(CC(C=CC=C4COC5C4(C(C=C(C5=NO)C)C(=O)O3)O)C)C)OC1C
Isomeric SMILES
CC[C@@H]1[C@H](CC[C@@]2(O1)C[C@@H]3C[C@H](O2)C/C=C(/C[C@H](/C=C/C=C/4\CO[C@H]\5[C@@]4([C@@H](C=C(/C5=N/O)C)C(=O)O3)O)C)\C)C.C[C@H]1CC[C@]2(C[C@@H]3C[C@H](O2)C/C=C(/C[C@H](/C=C/C=C/4\CO[C@H]\5[C@@]4([C@@H](C=C(/C5=N/O)C)C(=O)O3)O)C)\C)O[C@@H]1C
International Chemical Identifier key (InChIKey)
CKVMAPHTVCTEMM-ALPQRHTBSA-N
International Chemical Identifier (InChI)
InChI=1S/C32H45NO7.C31H43NO7/c1-6-27-21(4)12-13-31(40-27)17-25-16-24(39-31)11-10-20(3)14-19(2)8-7-9-23-18-37-29-28(33-36)22(5)15-26(30(34)38-25)32(23,29)35;1-18-7-6-8-23-17-36-28-27(32-35)21(4)14-26(31(23,28)34)29(33)37-25-15-24(10-9-19(2)13-18)39-30(16-25)12-11-20(3)22(5)38-30/h7-10,15,19,21,24-27,29,35-36H,6,11-14,16-18H2,1-5H3;6-9,14,18,20,22,24-26,28,34-35H,10-13,15-17H2,1-5H3/b8-7+,20-10+,23-9+,33-28-;7-6+,19-9+,23-8+,32-27-/t19-,21-,24+,25-,26-,27+,29+,31+,32+;18-,20-,22+,24+,25-,26-,28+,30-,31+/m00/s1
2D structure diagram/image available?
Yes
General status
Veterinary substance type
Anthelmintic agent; Ectoparasiticide
Substance groups
Micro-organism derived substance
Minimum active substance purity
>95%
Known relevant impurities
-
Substance origin
Natural
Mode of action
Opens glutamate sensitive chloride channels in neurons and myocytes of invertebrates, leading to hyperpolarisation of these cells and blocking of signal transfer.
Molecular targets
[GABA, Agonist]
CAS RN
129496-10-2
EC number
-
CIPAC number
-
US EPA chemical code
-
PubChem CID
-
Therapeutic Class
Antiparasitic products, insecticides and repellents: Milbemycins
ATCvet Code
QP54AB01
Controlled Drug?
No
Regulation 37/2010 MRL Classification
-
Molecular mass
1097.4
PIN (Preferred Identification Name)
None
IUPAC name
mixture of 70% (10E,14E,16E)-(1R,4S,5'S,6R,6'R,8R,13R,20R,24S)-6'-ethyl-24-hydroxy-5',11,13,22-tetramethyl-(3,7,19-trioxatetracyclo[15.6.1.14,8.020,24]pentacosa-10,14,16,22-tetraene)-6-spiro-2'-(tetrahydropyran)-2,21-dione 21-(EZ)-oxime and 30% (10E,14E,16E)-(1R,4S,5'S,6R,6'R,8R,13R,20R,24S)-24-hydroxy-5',6',11,13,22-pentamethyl-(3,7,19-trioxatetracyclo(15.6.1.14,8.020,24)pentacosa-10,14,16,22-tetraene)-6-spiro-2'-(tetrahydropyran)-2,21-dione 21-(EZ)-oxime
CAS name
(6R,25R)-5-demethoxy-28-deoxy-6,28-epoxy-25-ethyl-5-(hydroxyimino)milbemycin B mixture with (6R,25R)-5-demethoxy-28-deoxy-6,28-epoxy-5-(hydroxyimino)-25-methylmilbemycin B
Other status information
-
Relevant Environmental Water Quality Standards
-
Physical state
Crystalline solid
Formulations
Property
Product
Manufacturer
Authorisation Route
Legal Class (GB/UK)
Example products (past and present) using this active
Aderexa Chewable Tablets Krda d.d. Novo Mesto GB National authorisation Prescription only medicine to be authorised by a veterinarian (POM-V)
Mektix Chewable Tablets Kr GB National authorisation Prescription only medicine to be authorised by a veterinarian (POM-V)
Milbemax Novartis EU Mutually recognised procedure Prescription only medicine to be authorised by a veterinarian (POM-V)
Milprazon Krka d.d. GB National authorisation Prescription only medicine to be authorised by a veterinarian (POM-V)
Formulation and application details
Usually supplied in tablet form for oral administration
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
- - -
Solubility - In organic solvents at 20 °C (mg l⁻¹)
- - -
Melting point (°C)
- - -
Boiling point (°C)
- - -
Degradation point (°C)
- - -
Flashpoint (°C)
- - -
Octanol-water partition coefficient at pH 7, 20 °C
P
- - -
Log P
- - -
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
Max @ 246nm
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
 -
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)
- - -
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
Kd (mL g⁻¹)
- - -
Koc (mL g⁻¹)
-
Notes and range
-
Freundlich
Kf (mL g⁻¹)
- - -
Kfoc (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)
> 980
P4 P = Other non-EU, UK or US Governments and Regulators
4 = Verified data
Rat 		Moderate
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
- - -
- - -
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
- - -
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)
0.059
P4 P = Other non-EU, UK or US Governments and Regulators
4 = Verified data
Cyprinus carpio		 High
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)
> 100
P4 P = Other non-EU, UK or US Governments and Regulators
4 = Verified data
Daphnia magna		 Low
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 - Acute 7 day EC₅₀, biomass (mg l⁻¹)
- - -
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
- - -
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
- - -
Mesocosm study data
NOEAEC mg l⁻¹
- - -
NOEAEC mg l⁻¹
- - -
Marine bivalves – Acute EC₅₀ development (mg l⁻¹)
- - -
HUMAN HEALTH AND PROTECTION
General
Property
Value
Source; quality score; and other information
Interpretation
Threshold of Toxicological Concern (Cramer Class)
- - -
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
> 980
P4 P = Other non-EU, UK or US Governments and Regulators
4 = Verified data
Rat 		Moderate
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
200
P3 P = Other non-EU, UK or US Governments and Regulators
3 = Unverified data of known source
Rat as product		 -
Mammals - Inhalation LC₅₀ (mg l⁻¹)
> 5.0
P3 P = Other non-EU, UK or US Governments and Regulators
3 = Unverified data of known source
Rat 4 hr		 -
Other Mammal toxicity endpoints
- - -
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
Metabolised in the liver; biliary excretion
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
 -
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
No data found
A0 A = Chromosome aberration (EFSA database)
0 = No data
;
B0 B = DNA damage/repair (EFSA database)
0 = No data
;
C0 C = Gene mutation (EFSA database)
0 = No data
;
D0 D = Genome mutation (EFSA database)
0 = No data
;
E0 E = Unspecified genotoxicity type (miscellaneous data source)
0 = No data
 No data found
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
No data found No data found No data found
Respiratory tract irritant Skin irritant Skin sensitiser
?Possibly, status not identified
?Possibly, status not identified
 No data found
Eye irritant Phototoxicant  
?Possibly, status not identified
 No data found  
General human health issues
Harmful by inhalation and ingestion
Handling issues
Property
Value and interpretation
General
Non-corrosive
Not expected to auto-ignite; Not highly flammable
CLP classification 2013
Health: H302, H332
Environment: H400, H410
WHO Classification
Not listed (Not listed)
UN Number
None allocated
Waste disposal & packaging
-
Shelf-life, storage, stability and reactivity
-
TRANSLATIONS
Language
Name
English
milbemycin oxime
French
oxime de milbemycine
German
-
Danish
-
Italian
-
Spanish
-
Greek
-
Polish
-
Swedish
-
Hungarian
-
Dutch
-
Norwegian
-
Record last updated: 14/01/2024
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