Determination of Some Quinone Containing Drugs by Direct and Titrimetric First Derivative Spectrophotometric Methods

Abstract

Abstract The first-derivative spectra of some metal complexes of danthron and phanquone show well defined, prominent peaks. This can be made the basis of a spectrophotometric technique for the determination of both danthron and phanquone. Two spectrophotometric. procedures are described. The first-derivative spectrophotometric technique, found to be more sensitive than the direct-absorbance method when the metal complex is weakly absorbing, can be applied to the determination of danthron, and phanquone both in pure form and in pharmaceutical formulations. Danthron can be determined in the range of 0.48–5.7 mg using metal complexes. Phanquone can be determined in the range of 0.42–2.08 mg using iron (II), and 3.78–11.34 mg using cobalt (II). The second procedure is a first-derivative spectrophotometry titration for the determination of 0.096–0.57 mg of danthron and 0.048–1.0 mg of phanquone using the standard metal ion- solutions as titrants.