Colorimetric and Atomic Absorption Spectrometric Determination of Mucolytic Drug Ambroxol Through Ion-Pair Formation with Iron and Thiocyanate

Colorimetric and atomic absorption spectrometric methods have been developed for the determination of mucolytic drug Ambroxol. These procedures depend upon the reaction of iron(III) metal ion with the drug in the presence of thiocyanate ion to form stable ion-pair complex which is extractable in chloroform. The red-colored complex was determined either colorimetrically at 510 nm or by indirect atomic absorption spectrometry (AAS) via the determination of the iron content in the formed complex. The optimum experimental conditions for pH, concentrations of Fe3+ and SCN, shaking time, phase ratio, and the number of extractions were determined. Under the proposed conditions, linearity was obeyed in the concentration ranges 4.1x10-6 - 5.7x10-5 M (1.7-23.6 μg mL-1) using both methods, with detection limits of 4.6x10-7 M (0.19 μg mL-1) for colorimetry and 1.1x10-6 M (0.46 μg mL-1) for AAS. The proposed methods were applied for the determination of Ambroxol in tablet dosage forms. The results obtained were statistically analyzed and compared with those obtained by applying the high-performance liquid chromatographic method with diode-array detection.