Spectrophotometric Determination of Neomycin sulphate Via Association Ion Pair Complex with Erythrosine Dye

A simple, rapid, sensitive and accurate analytical method for the quantitative determination of neomycin sulphate (NEO) in its pure form and in pharmaceutical dosage forms was proposed. The method is based on the formation of an ionic complex between erythrosine dye and neomycin sulphate in a buffer medium at an acidic pH of 4.5 to obtain a colored product associated with the amount of NEO, which gives a maximum absorption at 560 nm. A calibration curve was drawn which was linear over the concentration range of 1.0-12.0 μg/mL with a correlation coefficient of 0.9999 and the molar absorptivity value was 4.8 × 104 L/mol. cm and Sandall index was 0.0128 μg/cm2. The LOD and LOQ values ​​were 0.106 and 0.353 μg/mL, respectively. The method was successfully applied for the determination of NEO present in pharmaceutical preparations and the recovery was good.