Determination of ampicillin in human plasma by high-performance liquid chromatography using ultraviolet detection

A high-performance liquid chromatographic method with isocratic elution has been developed for the determination of ampicillin in human plasma. The method comprises injection of the plasma after protein precipitation on to a reversed-phase C18 column, using phosphate buffer (pH3.5)-methanol as the mobile phase. The method involves UV detection at 225 nm. This method provides a simple technique for the rapid analysis of ampicillin within the concentration range 0.2-25 micrograms ml-1 with a high degree of accuracy and precision.