Determination of mezlocillin and its penicilloate and penilloate by high-performance liquid chromatography and stability of mezlocillin at different temperatures.

A method is described for the determination of mezlocillin and its metabolites penicilloic acid and penilloic acid in biological fluids by high-performance liquid chromatography. The stability of mezlocillin in serum and buffer was studied at different temperatures (4, -20, -70, and -196 degrees C) over a period of 6 months. Mezlocillin remained stable at -70 and -196 degrees C, whereas degradation was observed at -20 and 4 degrees C in serum and buffer.