Rapid and sensitive liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for the determination of clonidine in human plasma

A rapid and sensitive liquid chromatography–tandem mass spectrometry (LC–MS/MS) method has been developed and validated for the estimation of clonidine in human plasma. Clonidine was extracted from human plasma by using solid-phase extraction technique. Nizatidine was used as the internal standard. A Hypurity C18 (50 mm × 4.6 mm i.d., 5 μm particle size) column provided chromatographic separation of analyte followed by detection with mass spectrometry. The method involves a rapid solid-phase extraction from plasma, simple isocratic chromatography conditions and mass spectrometric detection that enables detection up to picogram levels with a total run time of 3.0 min only. The method was validated over the range of 50–2500 pg/mL. The absolute recoveries for clonidine (71.86%) and IS (69.44%) achieved from spiked plasma samples were consistent and reproducible.