[UV spectrophotometry in drug control. 31. Spectrophotometric behavior of drugs with dibenzo-p-thiazine chromophores].

The results of a systematic examination of the spectra of 34 drugs with dibenzo-p-thiazine chromophores in the ultraviolet and visible range were evaluated. The substances under study were subdivided into 10 different types corresponding to a different substitution in position 3 and in one case in position 5 of the phenothiazine ring system. All of these types are characterized by the bands E, K and B which are--with only a few exceptions--separated by well developed absorption minima.