Abstract: This invention pertains generally to the field of chemical synthesis and purification, and more specifically to methods of synthesizing and purifying certain 3,7-diaminophenothiazin-5-ium compounds (referred to herein as “diaminophenothiazinium compounds”) 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). The present invention also pertains to the resulting (high purity) compounds, compositions comprising them (e.g.

Abstract: Disclosed are methods of inducing or modelling the pathological state of an aggregating disease protein (ADP—e.g. tau protein) which is associated with a disease state in which the ADP aggregates pathologically (e.g. Alzheimer's disease) through an induced conformational polymerisation interaction, the method being characterised by the step of providing a membrane-localisable fusion protein comprising (i) an aggregating portion, which is derived from the ADP, or from a protein which initiates pathological aggregation of the ADP, (ii) a heterologous membrane-localising portion. Membrane-localisation of the ADP-based fusion protein is believed to cause the high-affinity capture site of the ADP protein to become exposed such that aggregation of further ADP, which may be native or heterologous to the system, to be promoted. The method can be carried out in vitro, or in cell- and animal-models, and may be used to screen for modulators of the aggregation process by monitoring aggregation e.g.