Determination of doxorubicin hydrochloride by visible spectrophotometry

Four simple and sensitive visible spectrophotometric methods (A-D) have been described for the assay of doxorubicin hydrochloride either in pure form or in pharmaceutical formulations. Method A was developed based on oxidation of the drug with Fe(III) to produce Fe(II), which subsequently reacts with 1.10- ortho-phenanthroline to form a red colored complex ( λ max: 510 nm) at pH 4.6. Method B involves the reduction of Folin-Ciocalteu (F-C) reagent by the drug and the reduced species formed possesses a characteristic intense blue color ( λ max: 770 nm). In methods C and D. oxidation of the drug with periodate at specified experimental conditions yields formaldehyde and dialdehyde, which in turn react either with 3-methyl-2-benzothiazolinone hydrazone hydrochloride to form an intensely brilliant blue cationic dye ( λ max: 620–670 nm. method C) or by condensation with phenylhydrazine hydrochloride (PHH) to form orange-red colored product ( λ max: 510 nm, method D) in the presence of potassium ferricyanide. All of the variables have been optimized and the reaction mechanisms presented. The concentration measurements are reproducible within a relative standard deviation of 1.0%.