Phenazine, 3-amino-7-(dimethylamino)-2-methyl-, hydrochloride
Soluble in water (50 mg/ml at 25° C), abs. alcohol (1.8%), and cellosolve (3.75%).
Neutral red (toluylene red, Basic Red 5, or C.I. 50040) is a eurhodin dye used for staining in histology. It stains lysosomes red. It is used as a general stain in histology, as a counterstain in combination with other dyes, and for many staining methods. Neutral Red is a weak cationic azine dye that is used extensively as a nuclear stain in a variety of biological stain applications. It is a pH indicator as well, changing color from red to yellow over the pH range 6.8-8.0. It is also incorporated into bacteriological growth media.
The high-purity neutral red is a common lysosomal probe that stains lysosomes a fluorescent red.A hydrochloride obtained by combining the free base of neutral red with one equivalent of hydrochloric acid. Neutral red acts as a pH indicator, changing from red to yellow between pH 6.8 and 8.0.It is used to stain embryonal tissues and supravital staining of blood. Can be used for staining Golgi apparatus in cells and Nissl granules in neurons. In microbiology, it is used in the MacConkey agar to differentiate bacteria for lactose fermentation. Neutral red can be used as a vital stain. Live cells incorporate neutral red into their lysosomes. As cells begin to die, their ability to incorporate neutral red diminishes. Thus, loss of neutral red uptake corresponds to loss of cell viability. It is also used to stain cell cultures for plate titration of viruses. Neutral red is added to some growth media for bacterial and cell cultures. It usually is available as a chloride salt.