A fast reverse-phase high performance liquid chromatographic tandem mass spectrometry assay for the quantification of clindamycin in plasma and saliva using a rapid resolution package.

A new method for the quantitative analysis of clindamycin in human plasma and saliva by liquid chromatography/electrospray ionisation tandem mass spectrometry (LC/ESI-MS/MS) has been developed using a rapid resolution C18 column (2.1 mm x 30 mm x 3.5 microm). A simple deproteinization procedure was applied to the samples before analysis. Multiple reaction monitoring (MRM) mode of precursor-product ion transitions for clindamycin (425.1/126.1) and the internal standard, lincomycin (407.2/126.0) was used. Chromatographic separation was achieved at 0.6 ml/min in less than 1.5 min, with improved peak resolution and sensitivity between drug and internal standard. The assay exhibited a linear dynamic range between 0.05 and 15.0 microg/ml and gave a determination coefficient of 0.991 or better. The limit of quantification of the method was 10 ng/ml in both biological samples. Intra-day and inter-day precision ranged from 7.5% to 11.5%. Good accuracy was observed for both the intra-day and inter-day assays (R.S.D. below +/-4%). The suitability of the developed method for the analysis of clindamycin in plasma and saliva samples was demonstrated by the measure of clindamycin in samples taken up to 6h after oral and intravenous administration of this drug in infectious patients.