Methylene Blue USP API (122965-43-9)

Methylene Blue USP Chemical Structure

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What is Methylene Blue?

Methylene Blue or Methylthioninium chloride is an organic compound that has several medical uses, and is also used as a dye or staining agent.

Methylene blue is an USFDA-approved treatment for acquired methemoglobinemia. It functions as an antidote for ifosfamide and cyanide toxicity and is also known to treat urinary tract infections. Furthermore, it is being investigated for its antimalarial and anti-Alzheimer properties. In addition to its medical applications in humans, methylene blue is also a widely used anti-fungal and anti-parasitic treatment in aquaculture.

Macsen Labs is a manufacturer and supplier of Injectable pharma grade Methylene Blue USP (Methylthioninium Chloride) of high purity grade for injection and other pharmaceutical applications. Along with United States Pharmacopoeia standard, we also supply Ph eur or EP, BP and CP grades of this API.

Macsen Labs group’s Methylene Blue Synthesis Process granted a patent from the Indian patent office

The Indian Patent Office granted a patent to Mr Achal Agrawal, CEO of Macsen Labs, Udaipur. The title of the patent is Novel Improved Method for Synthesis of Diaminophenothiazine Compounds and it concerns a novel process for synthesising the compound Methylthioninium Chloride or Methylene Blue. Macsen Labs has now achieved a unique position by this patent and from now nobody will be able to copy this process. Read more

Macsen Labs is a US FDA, EUGMP – WC, WHO GMP, ISO, Certified Manufacturer of high quality Methylene Blue USP based out of India and has substantial experience in manufacturing this API.

Name of Product Methylene Blue
Pharmacopoeial Name Methylene Blue USP
Synonyms Methylthioninium Chloride ; Basic Blue 9 ; Zinc free Methylene Blue ; C.I 52015 ; Methylene Blue Trihydrate
CAS No 122965-43-9
Molecular Formula C16H18ClN3S


SR. No Criteria Limit/Specification
1 Appearance and Odor Dark Green or Blue crystals or crystalline Powder having a bronze-like luster. Is odorless or practically so, and is stable in air. Its Solution in water and in alcohol are deeqblue in Golor
2 Relative Solubility Slightly Soluble in Water and in Alcohol
A. Infrared (IR) Absorption The IR Spectrum is concordant with the reference spectrum of Methylene Blue.
B. Retention Time (RT) The RT of the major peak of the Sample solution corresponds to that of the Standard Solution. As obtained in the Assay.
C. Identification of Chloride Meets the Requirements
A. Residue on Ignition NMT 0.15%
B. Arsenic PP
C. Copper or Zinc NMT 100 ppm of Zinc and NMT 200 ppm of Copper
5 Organic Impurities
Name Relative RT Acceptance Criteria NMT %
Azure B 0.8 2.5
Unspecified impurity-01 0.48 0.10
Unspecified impurity-02 0.6 0.10
Total Impurities (Excluding Azure- B) ---- 0.5
6 Loss on Drying (LOD) 8.0% to 22.0%
7 Bacterial EndotoxiRS Test NMT 2.5 USP Endotoxin Units/mL
8 Microbial Enumeration Test: Total aerobic microbial count (TAMC) NMT 102 cfu/g
9 ASSAY ( BY HPLC) 97.0% - 103.0% (on dried basis)


Q. Is methylene blue safe?

The use of methylene blue in therapeutic quantities (<2mg/kg) is considered to be safe. However, it can cause side effects at higher dose such as Serotonin Syndrome and Hemolytic Anemia.

Q. Does methylene blue kill cancer cells?

Methylene blue has demonstrated potential in the treatment of cancer as a result of its capacity to induce oxidative stress (which triggers apoptotic pathways, leading to programmed cell death) in cells and produce reactive oxygen species (ROS).

Q. Is methylene blue acidic or basic?

Methylene blue is a basic dye.

Q. Where can you buy methylene blue?

Macsen Drugs, a unit of Macsen Labs, is one of the leading cGMP manufacturers of Methylene Blue USP with WHO-GMP Certification, USFDA and USDMF registration.

Buy the best quality Methylene Blue USP used for topical antiseptic, urinary tract antiseptic, antidote injection for methemoglobinemia & cyanide poisoning from Macsen Labs.

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    Resources on Methylene Blue

    Methylene Blue | Chemistry, Uses & Side effects

    Methylene blue for treating Methemoglobinemia

    Methylene Blue & Covid-19 – Research So Far

    Staining with Methylene Blue | Different uses and examples

    Methylene Blue’s uses in Fish Aquaculture

    Methylene Blue Against Cyanide Poisoning

    Methylene Blue Injection: Indications, Dosage & Brands

    Methylene Blue in the treatment of Alzheimer’s

    Malaria Treatment with Methylene Blue

    Methylene Blue treatment for Lumpy Skin disease in cattle

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