Determination of imipenem and rifampicin in mouse plasma by high performance liquid chromatography–diode array detection

A high performance liquid chromatographic (HPLC) method for the determination of imipenem and rifampicin was developed and validated. The method involves plasma deproteinisation with methanol, gradient elution on a RP-18 column and diode array detection. Separation was carried out in 8 min using a mobile phase composed of methanol and 0.2 M borate buffer (pH 7.2). Imipenem and rifampicin were detected at 300 nm and 255 nm, respectively. A linear response was observed at plasma levels ranged between 0.3 and 30 μg mL−1 for imipenem and 1.5 and 20 μg mL−1 for rifampicin. The detection limits were 0.07 μg mL−1 and 0.47 μg mL−1 for imipenem and rifampicin, respectively. The method was applied to the determination of both compounds in mouse plasma samples.