High-performance liquid chromatographic determination of oxmetidine in human plasma: comparison of liquid-liquid and liquid-solid extraction techniques.

A preliminary liquid-solid sample preparation scheme (LSE) for the HPLC determination of oxmetidine in human plasma is compared with the existing liquid-liquid extraction. The LSE method shows great practical advantages, such as ease of preparation, saving of time, and smaller sample volumes, but needs to be investigated further with respect to robustness and the removal of an endogenous compound that interfered with the quantitation of oxmetidine at low concentrations.