Development of HPLC methodology for quantification of naltrexone and 6β-naltrexol in human plasma and its potential in alcohol use disorder treatment monitoring

Alcohol use disorder remains a significant public health challenge, with pharmacotherapy playing a critical role in treatment. Given the low rates of compliance and persistence in alcohol use disorder pharmacotherapy, the development of robust monitoring methods is essential to improve therapeutic outcomes. This study introduces a novel, environmentally friendly, high-performance liquid chromatography method for simultaneously quantifying naltrexone and its primary metabolite, 6β-naltrexol, in plasma while also reducing sample preparation time and simplifying extraction steps. Notably, it is the first high-sensitivity method in the literature that employs a UV detector, offering a cost-effective and accessible alternative to conventional detection techniques. Chromatographic separation was performed using a Kinetex EVO C18 (150 × 4.6 mm i.d.; 5 µm) column with a mobile phase composed of methanol and 0.1 % ortho-phosphoric acid in water (containing 0.1 % TEA) (20:80, v/v) at a flow rate of 0.4 mL/min. The column oven was set to 15°C, and the detection wavelength was 204 nm. The developed method was validated for selectivity, linearity, limit of detection, limit of quantification, precision, and accuracy in accordance with the guidelines set by the U.S. Food and Drug Administration. The validated method was successfully applied for the simultaneous determination and quantification of naltrexone and 6β-naltrexol in patients diagnosed with alcohol use disorder according to Diagnostic and Statistical Manual of Mental Disorders-5, who are undergoing treatment with naltrexone. This research provides a significant contribution to analytical research and drug monitoring. It enhances efficiency and sustainability in chromatographic analysis.