New spectrophotometric method for the determination of phenothiazine derivatives.

The use of a reduced solution of phosphomolybdic acid for the precipitation of phenothiazine derivatives offers excellent conditions for the assay of these compounds. The quantitative assay range for each of the phenothiazine derivatives was determined by the precipitation, proportionality, in accordance with the procedure used for chlorpromazine. The conditions offered by the new method make it possible to assay 12 phenothiazine derivatives.