Diazotised Suhphanilic Acid Reagent for the Determination of Trace Amounts of Cephadroxil in Aqueous Solution – Application to Pharmaceutical Preparations

ABSTRACT A simple spectrophotometric method for the determination of cephadroxil in aqueous solution is developed. The method is based on the coupling of cephadroxil with diazotised sulphanilic acid reagent in the presence of sodium hydroxide. The yellow azo-dye formed is water– soluble, stable, and shows maximum absorption at 445 nm. Beer’s law is obeyed over the range 10–240 mg/25 ml (0.4 –9.6 ppm) with a molar absorptivity of 1.73´10⁴ l.mol^-1cm^-1, Sandell’s sensitivity index of 0.0210 mg/cm², a relative error of –0.42 to +2.22 % and a relative standard deviation of ± 1.7 to ± 2.4 %, depending on the concentration level. The composition of the yellow azo-dye has been evaluated. The proposed method has been successfully applied to the determination of cephadroxil in various pharmaceutical preparations.