ABSTRACT
The aim of this study is to develop the first simultaneous method for quantification of neomycin and polymyxin B inthe presence of dexamethasone using High Performance Liquid Chromatography (HPLC) with an Evaporative LightScattering Detector (ELSD). The analysis was performed using a phenyl Waters X Bridge column, an evaporationtemperature of 50oC, and a nitrogen pressure of 320 kPa. The mobile phase consists of a combination of methanoland trichloroacetate acid (40 mM, pH 1.70–1.80) in gradient mode, flow rate at 1.0 ml/minute, detector gain of 6,and analysis time of 35 minutes. The linearity was achieved with a concentration of 100–500 µg/ml (r = 0.99955)for neomycin and concentration of 30–100 µg/ml (r = 0.99703) for polymyxin B. Recovery results were obtainedbetween 99.150% and 104.773% for neomycin and 96.538% and 105.139% for polymyxin B. The analysis samplefrom the market was found to be 102.27% for neomycin and 100.79% for polymyxin B. The result was compared tothe standard microbiological method. Based on the T-test results of two samples with a 95% confidence level (α =0.05), it was concluded that there was no significant difference between HPLC-ELSD and microbiological methodsfor determining neomycin and polymyxin B. The HPLC-ELSD method has a potential for routine analysis due toadvantages in terms of increasing precision, accuracy, and shorter testing time.