Voltammetric Determination of Amoxicillin in Solid Dosage Form

A method for accelerated determination of amoxicillin (AMO) in a solid dosage form (DF) that is based on preliminary extraction separation of the drug components [clavulanic acid (CLA) and AMO] followed by titration of its aqueous extract with a solution of photogenerated iodine obtained via irradiation of an auxiliary solution containing potassium iodide, a mixture of sensitizers (sodium eosinate-fluorescein-auramine taken in a 1:1:1 mole ratio), and acetate buffer solution (pH 5.6) was developed. Stabilization of the current in the amperometric setup circuit indicated the reaction was complete and; therefore, made it possible to regulate the AMO content in the DF because the content of titrant in the solution was controlled by a voltammetric method (amperometric titration with two polarized electrodes). Further irradiation of the solution and measurement of the generation time (required to replenish the lost titrant) also made it possible to regulate the antibiotic content in the DF. Extraction separation of the components made it possible to isolate from the model solution up to 94.5 and 98.0% of CLA and AMO, respectively. Lactulose present in the DF had an insignificant influence on photogeneration of the titrant. The amount of antibiotic found in the DF fell in the interval recommended by GPM.1.4.2.0009.15, which indicated that the quality of the drug met GMP standards. The analytical signal was observed to be linearly dependent on AMO concentration in the range 2.0 - 15.0 mg for the drug Augmentin (film-coated tablets 875 mg + 125 mg). The calculated limits of detection (LOD) and quantification (LOQ) for this drug were 2.17 and 0.72 mg based on the change of current and generation time, respectively. The developed determination method met the requirements set forth in the guidelines for validation of bioanalytical methods, was simple to implement, did not require expensive equipment, and, therefore, could be recommended for routine monitoring of the AMO content in the DF under the conditions of any control and analytical laboratory.

Automated summary

This study developed a method for accelerated determination of amoxicillin in solid dosage form. The method involved preliminary extraction separation of the drug components followed by titration of its aqueous extract. The developed method met the requirements set forth in the guidelines for validation of bioanalytical methods and could be recommended for routine monitoring of the amoxicillin content in the solid dosage form.