DETERMINATION OF INDIRUBIN

The method of determination of indirubin is described in this paper.Indirubin samples were dissolved in tetrahydrofuran and optical density were measured at 540 nm and 610 nm with model 72 spectrophotometer within 8 hrs. The quantities of indirubin and indigotin were calculated from formula (5) and (6).This determination is not interfered by the presence of indigo brown because of its insolubility.With this method the recovery of indirubin is 98.20±.0.87% and that of indigotin is 98.15±1.87%. The maximum deviation of the determination of indirubin tablets is 0.38～1.21%.