Novel colorimetric approach for amikacin estimation in pure powder and its pharmaceutical formulations

A sensitive and validated colorimetric method was developed and optimized for the estimation of amikacin sulfate in pure and pharmaceutical dosage forms. Ascorbic acid was used as a chromogenic reagent to produce a stable color complex with amikacin that absorbs strongly at 390nm and 540nm. Several experimental factors were evaluated to maximize color development and stability, including solvent, reagent concentration, reaction time, and temperature. Optimal conditions were found using DMSO solvent, 0.2% ascorbic acid, and 40 minutes reaction time at 25°C. Under these conditions, Beer's law was obeyed in the range of 40-200μg/mL with high correlation coefficients, indicating excellent linearity. The method was validated in terms of linearity, accuracy, precision, detection/quantitation limits, and application to actual samples as per ICH guidelines. Recovery studies showed nearly 101% accuracy. Low relative standard deviations reflected high precision. Limits of detection/quantitation were 19-57μg/mL, enabling reliable analysis even at low concentrations. The method quantified amikacin content in injections, giving 98-102% accuracy. Statistical comparisons to a validated method gave no significant differences, confirming this approach provides equivalent results.