Quantitative analysis of Cephalexin in 250mg powdered suspension via High Performance Liquid Chromatography (HPLC)

Abstract

     An accurate and sensitive method was developed for qualitative and quantitative analysis of Cephalexin (CPN) in powdered suspension using Ion–Pair Chromatography (IPC–HPLC) with PDA detector. CPN is a zwitterion and the degree of ionization of CPN affects the retention of compound in the reversed phase chromatographic column through investigating the concentration of buffer solutions at pH = 3.0 and pH = 7.0. Experimental results optimized the chromatographic conditions with a flow rate 1.5  mL.min^-1  and the chromatograms obtained meet the symmetry coefficient. At the same time, optimizing mobile phase composition at pH = 3.0, symmetrical peak shape chromatography and retention time have repeatability with relatively standard deviation between injections %RSD = 0.12 % (< 2.0 %). Chromatography parameters were stainless steel RP-18 column (250 mm x 4.6 mm i.d., 5 μm particle size), at 40 ⁰C. The isocratic mobile phase was buffer solution at pH = 3.0. The determinations were performed using PDA detector at 254 nm. Samples were prepared with mobile phase and the volume injected was 20 μL. Calibration graph was in the range of (0.102 - 0.812) mg. mL^-1 with a correlation coefficient of 1. The method showed adequate precision, with a relative standard deviation (%RSD) smaller than 2.0 %. The method was applied successfully to determine the content of CPN in powdered suspension with recovery of (99.11 - 100.49) % và %RSD = 0.66.