Extractive spectrophotometric determinations of some phenothiazine derivatives in pharmaceutical preparations.

Two sensitive methods for the determination of phenothiazine derivatives based on the formation of coloured salts of these drugs formed with Brilliant Blue or Orange-II in the presence of 0.1 M HCl are described. The ion pair salts formed are quantitatively extracted into chloroform and the dried chloroform solutions analyzed using spectrophotometry.