Disclosed are methods of synthesis and/or purification of certain 3,7-diamino-phenothiazin-5-ium compounds (diaminophenothiazinium compounds) including Methylthioninium Chloride (MTC) (Methylene Blue), and the resulting high purity characterized by a purity greater than 98%, and very low levels of heavy metals and organic impurities Azure A, B, C and MVB. Also disclosed are methods of treatment of a tauopathy or methemoglobinemia in a patient in need thereof, comprising administering to the patient a therapeutically effective amount of the high-purity diaminophenothiazinium compound.

Disclosed are methods of synthesis and/or purification of certain 3,7-diamino-phenothiazin-5-ium compounds (diaminophenothiazinium compounds) including Methylthioninium Chloride (MTC) (Methylene Blue), and the resulting high purity characterized by a purity greater than 98%, and very low levels of heavy metals and organic impurities Azure A, B, C and MVB. Also disclosed are methods of treatment of a tauopathy or methemoglobinemia in a patient in need thereof, comprising administering to the patient a therapeutically effective amount of the high-purity diaminophenothiazinium compound.

This disclosure pertains generally to the field of chemical synthesis and purification, and more specifically to methods of synthesizing and purifying certain 3,7 diamino-phenothiazin-5-ium compounds (referred to herein as diaminophenothiaziniumcompounds) including Methythioninium Chloride (MTC) (also known as Methylene Blue). In one embodiment, the method comprises the steps of, in order: nitrosylation (NOS); nitrosyl reduction (NR); thiosulfonic acid formation (TSAF); oxidative coupling (OC); Cr(VI) reduction (CR); isolation and purification of zwitterionic intermediate (IAPOZI); ring closure (RC); chloride salt-formation (CSF); one of: sulphide treatment (ST); dimethyldithiocarbamate treatment (DT); carbonate treatment (CT); ethylenediaminetetraacetic acid treatment (EDTAT); organic extraction (OE); and recrystallisation (RX). Also disclosed resulting (high purity) compounds, compositions comprising them (e.g., tablets, capsules), and their use in methods of inactivating pathogens, and methods of medical treatment and diagnosis, etc., for example, for tauopathies, Alzheimer's disease (AD), skin cancer, melanoma, viral diseases, bacterial diseases, or protozoal diseases.

A process for the purification of diaminophenothiazinium compounds, and particularly of methylene blue, is described. The process provides for simple and affective purification by reduction of the post-synthesis or commercially available diaminophenothiazinium compound to form a reduced complex thereof. This can then be purified in a more straightforward manner than the original compound by, for example, recrystallization before being allowed to oxidize back to the diaminophenothiazinium compound.

Disclosed herein are methods for preparing ultrapure diaminophenothiasinium compounds with high solubility in solutions, e.g., water, and the compositions provided therefrom.

A composite of graphene oxide and PTZ that may further entrap a redox enzyme. This composite can be used for detecting the substrate of the redox enzyme in a sample or for producing an acid byproduct of the enzymatic reaction. Furthermore, provided herein is a kit which includes a composite of graphene oxide and PTZ entrapping a redox enzyme and means for connecting the entrapping composite to a source of electricity.

Disclosed are methods of synthesis and/or purification of certain 3,7-diamino-phenothiazin-5-ium compounds (diaminophenothiazinium compounds) including Methylthioninium Chloride (MTC) (Methylene Blue), and the resulting high purity characterized by a purity greater than 98%, and very low levels of heavy metals and organic impurities Azure A, B, C and MVB. Also disclosed are methods of treatment of a tauopathy or methemoglobinemia in a patient in need thereof, comprising administering to the patient a therapeutically effective amount of the high-purity diaminophenothiazinium compound.

Disclosed are methods of synthesis and/or purification of certain 3,7-diamino-phenothiazin-5-ium compounds (diaminophenothiazinium compounds) including Methylthioninium Chloride (MTC) (Methylene Blue), and the resulting high purity characterized by a purity greater than 98%, and very low levels of heavy metals and organic impurities Azure A, B, C and MVB. Also disclosed are methods of treatment of a tauopathy or methemoglobinemia in a patient in need thereof, comprising administering to the patient a therapeutically effective amount of the high-purity diaminophenothiazinium compound.

A method of forming a 3-phenylimino-3H-phenothiazine or a 3-phenylimino-3H-phenoxazine mediator includes providing a first reactant including phenothiazine or phenoxazine, providing a first solvent, providing a second reactant and providing a second solvent. The first reactant, first solvent, second reactant and second solvent are combined to form a reactants solution. Sodium persulfate is added to the reactants solution to couple the first and second reactants resulting in a reaction solution including the 3-phenylimino-3H-phenothiazine or the 3-phenylimino-3H-phenoxazine mediator.

A method of forming a 3-phenylimino-3H-phenothiazine or a 3-phenylimino-3H-phenoxazine mediator includes providing a first reactant including phenothiazine or phenoxazine, providing a first solvent, providing a second reactant and providing a second solvent. The first reactant, first solvent, second reactant and second solvent are combined to form a reactants solution. Sodium persulfate is added to the reactants solution to couple the first and second reactants resulting in a reaction solution including the 3-phenylimino-3H-phenothiazine or the 3-phenylimino-3H-phenoxazine mediator.