Development of a liquid chromatographic method to monitorization of medazepam and lorazepam in plasma and its validation

This study, it was aimed to develop a simple, sensitive and reliable high-performance liquid chromatographic method for simultaneous analysis of medazepam and lorazepam based on the solid-phase extraction from human blood. For the pretreatment of (500 µL) plasma sample, an efficient extraction method was developed and optimized. Separation was carried out with an ODS reverse phase C18 analytical column (150x4.0mm, 3µm). The composition of 20 mM KH2PO4 buffer and methyl cyanide (6:4, v/v) was employed as the mobile phase in the chromatographic system. The ultraviolet detector was set at 220nm. Determination of coefficients values was found as 0.9928 (r2) between 500-2500 ng/mL concentrations for medazepam and 0.9983 between 20-300 ng/mL for lorazepam. It was observed that the method has successful validation test results from accuracy, sensitivity, recovery, precision, and robustness in accordance with ICH Q2R1 guidelines. The method is recommended for monitoring blood levels of lorazepam and medazepam in toxicology laboratories. © 2023, Istanbul Medipol University. All rights reserved.