A simple, rapid, sensitive, precise and accurate high-performance liquid chromatographic (HPLC) method with ultraviolet detection at wavelength of 205nm has been validated for the simultaneous determination of amoxicillin and clavulanic acid in human serum. Serum samples were deproteinized with methanol. The separation of 2 obtained compounds was achieved using a reversed phase C8 column and a mobile phase, consisting of acetonitrile-phosphate solution. The calibration curves were linear over the concentration range of 0.625 – 10 g.ml-1 for amoxicillin and 0.3125 – 5 g.ml-1 for clavulanic acid. The quantitative limits are 0.625 and 0.3125 g.ml-1 for amoxicillin and clavulanic acid. Analytical recoveries from human serum ranged from 93 to 96% for both components. This method was fully validated. It allows the simultaneous assay of amoxicillin and clavulanic acid in biomedical applications. This method has been successfully applied to a pilot pharmacokinetic study in 3 healthy volunteers after a single oral administration of amoxicillin and clavulanic acid combination
Amoxicillin ; Clavulanic Acid ; Serum ; Chromatography, High Pressure Liquid

UV - spectrophotometric (UV) and high performance liquid chromatographic methods (HPLC) were described in determining amoxicillin and clavulanic acid in pharmaceutical preparations. Spectrophotometrically, amoxicillin was determined by measuring the absorbance values at 320 nm in buffer-CuS04 solution (pH 5.2) for amoxicillin and at 313 nm in imidazol solution (pH 6.8) for clavulanic acid. Beer's Law was obeyed in range 12 - 32mg. ml-1 for amoxicillin and 12 - 22 mg. ml-1 for clavulanic acid. The simultaneous HPLC method depended upon using a reserved phase RP18 column at ambient temperature with a mobile phase consisting of methanol - phosphate solution pH 4.4 (4:96) at a flow rate 1ml.min-1. Quantitation was achieved by UV detection at 220 nm. Calibration curve was linear over the concentration range 50-150 mg. ml-1 for amoxicillin and 15-35 mg. ml-1 for clavulanic acid. Both spectrophotometry and HPLC method showed good linear correlation, precision and accuracy. The obtained results from spectrophotometry and HPLC method showed no significant difference. Both methods were successfully applied to the assay of commercial tablets. The procedures were rapid, simple and suitable for quality control applications
Pharmaceutical Preparations ; Amoxicillin ; Clavulanic Acid