A new simultaneous derivatization and microextration method for the determination of memantine hydrochloride in human plasma

A simple and sensitive method for simultaneous derivatization and hollow fiber liquid phase microextraction (HF-LPME) followed by high performance liquid chromatography–fluorescence detection (HPLC–FL) to determine memantine hydrochloride (MT) in human plasma was developed. The derivatization and microextraction was combined to a single step to ensure the precision. What is more, the derivatization reaction accelerated the mass transfer during the process of microextraction. The hollow fiber was filled with cyclohexane and dansyl chloride (derivatization agent) as acceptor phase and submersed in the alkalinized plasma sample. The system was submitted to stirring at 800 rpm for 50 min at 40 °C. Different experimental parameters were systematically evaluated by response surface methodology. Under the optimized conditions, the calibration curve was linear in the range of 1–100 ng/mL (r = 0.9991) with a limit of detection of 0.1 ng/mL (S/N = 3). The precision estimated as the relative standard deviation (RSD) was less than 4.5% and the accuracy was 94.3–100.7%. The present method was successfully applied to determine MT in human plasma samples.