• Milbemycin Oxime

click on thumbnail to zoom
SKU: M015

Price: make selection(s)

Milbemycin Oxime is a semi-synthetic, broad-spectrum macrocyclic lactone (ML), containing a 16-membered macrocyclic ring.   Milbemycin Oxime is produced by fermentation of the soil-dwelling Streptomyces hygroscopicus subsp. aureolacrimosus followed by chemical modification (oxidation and oximation) of  Milbemycin mixture A3 and A4 (~ 30:70 ratio).   It is commonly used as an insecticide, parasiticide, and nematocide.  Milbemycins are closely related to the avermectin class. 

Milbemycin Oxime is sparingly soluble in DMSO.

We also offer:

  • Milbemycin A3 (M057)
  • Milbemycin Oxime (M015)

    CAS Number


    Molecular Formula

    Milbemycin A3 - C31H43NO7
    Milbemycin A4 - C32H45NO7

    Molecular Weight

    541.7 (A3), 555.7 (A4)

    Mechanism of Action

    In invertebrates, macrocyclic lactons (MLs) can open ligand-gated chloride channels such as glutamate-sensitive chloride ion channels. When bound, MLs causes an influx of chloride into the parasite neurons leading to hyperpolarization, paralysis, and death.

    In mammals, MLs bind to gamma-aminobutyric acid type A-gated chloride channels (GABAA receptors). GABA is the primary neurotransmitter in the brain. MLs are believed to bind to GABAA receptors, which are only present in the central nervous system.

    Milbemycin Oxime has surprising intrinsic antifungal activity.  It inhibits fungal growth by inhibiting ATP-binding cassette (ABC) transporters.  Fungicidal activity could be related to ROS formation in these species.

    Storage Conditions


    Tariff Code



    Milbemycin Oxime is active against arthropods, nematodes, insects, and mites (Sarcoptes, Demodex).  It is also active against fungi including C. albicans, C. glabrata.


    Insect Biology Applications

    Milbemycin Oxime was investigated in cat models with fourthstage larvae and adults of Ancylostoma tubaeforme and was able to reduce egg count by 99% (Humbert-Droz et al, 2004).

    Milbemycin A3 derivatives (specifically 5-keto-5-oxime derivatives) were able to control natural microfilariae infestation caused by Dirofilaria immitis in canine models more effectively than Milbemycin A3 parental compounds (Tsukamoto et al, 1991).





    White or light yellow powder



    Impurity Profile

    Impurity G: Not more than 2.0%
    Impurity E: Not more than 0.7%
    Impurity H: Not more than 0.5%
    Impurity I: Not more than 0.5%
    Any other impurity: Not more than 0.2%
    Total impurities: Not more than 3.5%


    (A3 + A4): 95.0 - 102.0%
    A3 Ratio: Not more than 0.20
    A4 Ratio: Not less than 0.80

    Residual Solvents

    Ethanol: Not more than 5000 ppm
    Acetone: Not more than 5000 ppm
    n-Heptane: Not more than 5000 ppm
    Methanol: Not more than 3000 ppm
    4-Dioxane: Not more than 380 ppm
    Methylene chloride: Not more than 600 ppm
    Chloroform: Not more than 60 ppm



    Humbert-Droz E, Buscher G, Cavalleri D, and Junquera P (2004)  Efficacy of Milbemycin Oxime against fourthstage larvae and adults of Ancylostoma tubaeforme in experimentally infected cats. Vet. Rec. 154(5):140-143

    Kornis GI (1995)  Avermectins and Milbemycins. In: Godfrey CRA, ed. Agrochemicals from natural products. Marcel Dekker. New York, NY  pp 215–255

    Merola VM and Eubig PA (2012)  Toxicology of avermectins and milbemycins (macrocylic lactones) and the role of P-glycoprotein in dogs and cats. Vet. Clin. North Am. Small Anim. Pract. 42(2): 313-333

    Nakao T, Banba  and Hirase K (2015)  Comparison between the modes of action of novel meta-diamide and macrycyclic lactone insecticides on the RDL GABA receptor. Pest. Biochem. and Physiol. 120:101-108   PMID 25987227

    Okazaki T et al.(1983)  Milbemycins, a new family of macrolide antibiotics: Producing organism and its mutants J Antibiot. 36:438  PMID  6853372

    Silva, LV (2016)  Milbemycins: More than efflux inhibitors for fungal pathogens. 57:873-886.

    Takiguchi Y et al (1980) Milbemycins, a new family of macrolide antibiotics: Fermentation, isolation and physico-chemical properties. J Antibiot. 33:1120  PMID 7451362

    Takiguchi Y et al (1983)  Milbemycins, a new family of macrolide antibiotics. Fermentation, isolation and physico-chemical properties of Milbemycins D, E, F, G, and H. J Antibiot.(Tokyo). 36(5):502-508  PMID 6874568

    Tsukamoto Y. et al (1991)  Synthesis of 5-keto-5-oxime derivatives of Milbemycins and their activities against microfilariae. Agric. Biol. Chem 55(10):2615-2621  PMID 1368759

    Vercruysse J, Rew RS, eds. (2002)  Macrocyclic lactones in antiparasitic therapy. New York: CABI

Other Items In This Category