Simultaneous Determination of Amoxicillin, Lansoprazole, and Levofloxacin in Pharmaceuticals by HPLC with UV-Vis Detector

In this study, a specific and rapid high-performance liquid chromatography (HPLC) method has been developed and validated for the simultaneous determination of amoxicillin, lansoprazole, and levofloxacin in pharmaceuticals. Paracetamol was used as internal standard (IS) in the measurements. UV-Vis absorption spectra of the analytes and the IS were taken for the determination of suitable absorption wavelength of UV-Vis detector (diode array detector, DAD) in the HPLC instrument. A reverse-phase C18 column was used in the separation and determination of amoxicillin, lansoprazole, and levofloxacin together with the IS. The pharmaceutical analytes were quantified by the UV-Vis diode array detector in the HPLC using MeOH-0.01 M CH3COONH4 (70:30) as the mobile phase. The linear calibration curves of them were measured in the ranges of 15-40 mg/L, 2.5-15.0 mg/L, and 7.5-20.0 mg/L for amoxicillin, lansoprazole, and levofloxacin, respectively. Excellent calibration correlations (R-2: 0.9942, 0.9997, and 0.9974) were obtained. The percentage recoveries of the amoxicillin, lansoprazole, and levofloxacin in commercial pharmaceuticals were obtained as 105.5%, 98.57%, and 102.5%, respectively. The results showed that amoxicillin, lansoprazole, and levofloxacin together with paracetamol IS could be separated and determined simultaneously with low LOD and LOQ values using the proposed HPLC method.