Preparation and pharmacokinetic evaluation of a sertraline-methylpropyphenazone prodrug: a comparative metabolic study on the plasma and brain tissues of rats using LC-MS/MS analysis

Abstract

A mutual prodrug of sertraline-methylpropyphenazone (SER-MP) was prepared and characterized using a spectral method. The yield of the prepared SER-MP was 90%, and its purity reached 98.8%. The metabolic fate of the prepared SER-MP versus sertraline (SER) was investigated in the plasma and brain tissues of rats. A solid-phase extraction procedure was developed and validated for the optimal recovery of SER, 3-hydroxymethylpropyphenazone (3-OHMP), and SER-MP from plasma and brain tissues. The extraction efficiency for the targeted analytes was improved from 93.5% to 98.0% using Chromabond® C8-100 mg solid-phase extraction columns. A high-performance liquid chromatography-triple-quad-mass spectrometric method was developed and validated to quantify the SER, SER-MP, and potential metabolites. The pharmacokinetic parameters showed that the time to reach the maximum plasma concentration (t_max) for both SER and SER-MP was 6 hours, and the maximum plasma concentration of SER-MP reached 192 ng mL⁻¹ with an elimination half-life time of 50 hours. The plasma level of SER, which was released as a metabolite of orally administered SER-MP, was increased by 2.4 times compared to SER HCl administered at equimolar doses. The concentration of SER-MP in the rat brains remained approximately stable at 100 ng g⁻¹ for 0.5 to 192 hours. The serotonin level in the rat brain homogenate was 50 to 90 ng g⁻¹ for both the group receiving SER and that receiving an equal molar dose of SER-MP. This observation was consistent during a time range of 1 to 192 h from oral administration. Thus, this approach could lead to the development of more efficient antidepressant therapies with reduced side effects. The findings indicate that SER-MP could minimize serotonin syndrome risks by maintaining steady serotonin levels in the brain, thus improving patient safety and compliance.