Ultra-fast UPLC-MS/MS approach for estimating X-376 in human liver microsomes: Evaluation of metabolic stability via in silico software and in vitro analysis.

X-376 is a novel anaplastic lymphoma kinase (ALK) inhibitor that is capable of penetrating the blood brain barrier. This makes it suitable for use in patients with ALK-positive non-small cell lung cancer (NSCLC) who have metastases in the central nervous system. This study developed a highly sensitive, fast, eco-friendly, and reliable UPLC-MS/MS approach to quantify X-376 in human liver microsomes (HLMs). This approach was used to evaluate X-376's metabolic stability in HLMs in vitro. The UPLC-MS/MS analytical technique validation followed US-FDA bio-analytical method validation guidelines. StarDrop software, containing P450 metabolic and DEREK modules, was utilized to scan X-376's chemical structure for metabolic lability and hazardous warnings. X-376 and Encorafenib (ENF as internal standard) were resoluted on the Eclipse Plus C18 column utilizing an isocratic mobile phase method. The X-376 calibration curve was linear from 1 to 3000 ng/mL. The precision and accuracy of this study's UPLC-MS/MS approach were tested for intra- and inter-day measurements. Inter-day accuracy was -1.32% to 9.36% while intra-day accuracy was -1.5% to 10.00%. The intrinsic clearance (Cl) and in vitro half-life (t) of X-376 were 59.77 mL/min/kg and 13.56 min. The high extraction ratio of X-376 supports the 50 mg twice-daily dose for ALK-positive NSCLC and CNS metastases patients. In silico software suggests that simple structural changes to the piperazine ring or group substitution in drug design may improve metabolic stability and safety compared to X-376.