GRADIENT MULTIPEAK LIQUID-CHROMATOGRAPHIC METHOD FOR DETERMINATION OFARDACIN IN BULK CHEMICAL AND PREMIX FORMULATIONS

A liquid chromatographic (LC) method was developed for the determinati on of ardacin in bulk chemical (78 to 100%, w/w anhydrous) and premix formulations (3.3 to 26.4%, w/w), The method is based on reversed-phas e LC resolution of ardacin components and detection by UV absorbance a t 220 nm. Ardacin has 10 components, and each component can be quantit ated separately, Total ardacin is determined by summing the areas of t he in component peaks, Calculations are performed using an external st andard approach, The method is linear for ardacin at 50 to 150 mu g/mL . The method accuracy for a typical bulk chemical is +/- 1.5%, w/w (re lative standard deviation [RSD], 1.6%), and recovery from a typical pi lot scale premix is 99.9% (RSD, 3.4%), The method is useful for monito ring stability during storage.