Mexiletine hydrochloride is an orally active ClaI antiarrythmic agent.A sensitive and specific high-performance liquid chromatography(HPLC) method has been developed for the determination and quantification of mexiletine in human urine and plasma. hollow fiber liquid-liquid-liquid microextraction (HF-LLLME) followed by a reverse-phase HPLC with a pre-column derivatization with ortho-phthalaldehyde (OPA) and fluorescence detectionfor analysis of MEX in human urine and plasma [1,2]. Chromatographic separation was performed on a C-ODS column (shim pack, 50mm × 4mm i.d with 3µm particle size with mobile phase consisting of acetonitrile and water (80:20, v/v) (isocrtic) and the flow rate was set at 1ml/min; followed by fluorescence detection(ex=350nm and em=445nm). All variables effecting the exraction of analyte including acceptor organic solvent type, concentration of NaOH in donor phase, ionic strength of the sample and exraction time were studied.The assay was linear in the concentration range 1-200µg L -1 (r 2 ?0.996) . The relative standard deviation for urine was lower than 0.8% and for plasma was lower than 1.6% for both urine and plasma.The enrichment factor was 153 and the detection limit is 0.3 .the method was successfully applied for the analysis of MEX in urine and plasma samples.
