A New Method for the Determination of Amisulpride in a Small Volume (200 μL) of Human Saliva Using LC-DAD Supported by SPE

(1) Background: The concentration of amisulpride, an atypical antipsychotic drug, is most often determined in the blood, with many inconveniences. An alternative may be to use saliva as a diagnostic material for this purpose. The development of a method to determine amisulpride in saliva using a small volume of biological material could significantly improve patient comfort during Therapeutic Drug Monitoring (TDM). (2) Methods: Therefore, the aim of this study was to develop a method to determine amisulpride in 200 mu L of saliva using solid-phase extraction for isolation and liquid chromatography with a diode array detector (LC-DAD) for quantitative analysis. (3) Results: The method was validated by determining its linearity in the concentration range 5-500 ng/mL (R-2 > 0.99), and the intra- and inter-day precision expressed as coefficient of variation (CV%) did not exceed 9%. (4) Conclusions: The developed method was used to determine the salivary concentration of amisulpride in patients treated with the studied compound, confirming its usefulness in TDM.