Determination of β-lactam Antibiotics in Pharmaceutical Preparations by Uv-visible Spectrophotometry Atomic Absorption and High Performance Liquid Chromatography

The determination amoxicillin, ampicillin and cephalexin was studied by complexation of the antibiotics with Au(III) and Hg(II) ions in bulk and pharmaceutical preparations using uv-visible spectrophotometry, atomic absorption, and HPLC techniques. Optimum conditions for complex formation were fixed at pH 4 and (2-4) for Au(III) and Hg(II) complexes respectively, heating temperature at (60°C) and heating time for (10 minute). All complexes were extracted from aqueous solution with benzyl alcohol prior to measurements except in the case of HPLC. The L:M ratios for all complexes were determined and stability constants were calculated using mole ratio method. The Beer's law was obeyed over the concentration range (5-60) and 5-50 µg/ml of antibiotics for Au(III) and Hg(II) complexes using colorimetric method and (1-25 µg/ml) of Au(III) for FAAS. The linearity for HPLC method was (10-110 and 10-120 µg/ml) respectively. The correlation coefficients (r) were (0.9981-0.9997). Generally, the highest sensitivity was recorded by FAAS.