Spectrophotometric determination of amodiaquine and sulfadoxine in pharmaceutical preparations

A new rapid and sensitive spectrophotometric method was developed for the determination of amodiaquine and sulfadoxine in both pure and dosage forms. The proposed method is based upon the reaction of amino group with sodium nitrite followed by beta-naphthol that produces a colored compound. These species exhibit the maximum absorption at 505 nm for amodiaquine and at 470 nm for sulfadoxine with molar absorptivity of 6.83 x 10(4) and 3.74 x 10(4) L mol(-1) cm(-1) respectively The range of linearity for the both drugs is 4 - 60 mu g mL(-1). The optimum reaction conditions and other analytical parameters have also been investigated. The influence of substrates commonly employed as excipients with these drugs have been studied. The proposed method is applicable for the determination of these drugs in pharmaceutical formulations. The results demonstrated that the method is accurate, reproducible and comparable to the official method.