Methylene Blue

Toxicity

LD50 = 1180 mg/kg ( Rat ).

Description

Methylene blue is one of the oldest organic dyes. It was first prepared in 1876 by H. Caro—BASF’s research director at the time—for use as a cotton dye. In 1880, microbiologist R. Koch established it as a medical stain. It is also used as an indicator for redox reactions, a photosensitizer for generating singlet oxygen, and a drug to treat methemoglobinemia, among other conditions. Until recently, dyestuff-grade methylene blue was used in medicine, but?a pharmaceutical grade is now under development.

The Uses of Methylene Blue

Methylene Blue, 1% w/v aqueous solution is used as a dye in different staining procedures viz. Wright's stain and Jenner's stain. It also serves as an indicator and medicine. Further, it is used to examine RNA and DNA under the microscope or in a gel. It is widely used as a redox indicator in analytical chemistry. It is also used in the sulfide analysis.

Background

Methylene blue is an oxidation-reduction agent. The intravenous form of methylene blue is approved by the FDA for the treatment of pediatric and adult patients with acquired methemoglobinemia. Historically, it has been widely used in Africa to treat malaria, but now it disappeared when chloroquine (CQ) and other drugs entered the market. Its use as an urinary tract antiseptic has also been investigated.
Methylthioninium chloride (INN, or methylene blue, proposed trade name Rember) is an investigational drug being developed by the University of Aberdeen and TauRx Therapeutics that has been shown in early clinical trials to be an inhibitor of Tau protein aggregation. The drug is of potential interest for the treatment of patients with Alzheimer's disease.

Indications

Indicated for the treatment of pediatric and adult patients with acquired methemoglobinemia.
Other clinical applications of methylene blue include improvement of hypotension associated with various clinical states, an antiseptic in urinary tract infections, treatment of hypoxia and hyperdynamic circulation in cirrhosis of liver and severe hepatopulmonary syndrome, and treatment of ifofosamide induced neurotoxicity.

What are the applications of Application

Methylene blue is a polyaromatic stain

Metabolism

Following distribution into tissues, rapidly reduced to leukomethylene blue (leucomethylthioninium chloride). Metabolism to leucomethylene blue may be less efficient in neonates than in older individuals.