Determination of clindamycin in human plasma by liquid chromatography electrospray tandem mass spectrometry: application to the bioequivalence study of clindamycin

A simple, sensitive and specific liquid chromatography-electrospray tandem mass spectrometry (LC-MS-MS) method for the determination of clindamycin (I ) was developed. Both I and verapamil (II, internal standard) were analyzed using a C-18 column with a mobile phase of 80% acetonitrile-0.01% trifluor oacetic acid. Column eluents were monitored by electrospray tandem mass spe ctrometry. Multiple reaction monitoring (MRM) using the parent to daughter combinations of m/z 425-->126 and 455-->165 was used to quantitate I. A lim it of quantitation of 0.0500 mu g/ml was found. The assay exhibited a Linea r dynamic range of 0.0500-20.0 mu g/ml and gave a correlation coefficient ( r(2)) of 0.998 or better. The chromatographic run time was approximately 2 min. The intra-batch precision and accuracy of the quality controls (QCs, 0 .0500, 0.150, 1.50, 15.0 and 20.0 mu g/ml) were characterized by coefficien ts of variation (CVs) of 5.13 to 13.7% and relative errors (REs) of -4.34 t o 4.58%, respectively. The inter-batch precision and accuracy of the QCs we re characterized by CVs of 4.35 to 8.32% and REs of -10.8 to -4.17%, respec tively. The method has successfully been applied to the analysis of samples taken up to 12 h after oral administration of 300 mg of I in healthy volun teers. (C) 1999 Elsevier Science B.V. All rights reserved.