Quantification of buparlisib in human liver microsomes employing an ultra-fast, sensitive UPLC-MS/MS method: in vitro and in silico metabolic stability evaluation

Abstract

Buparlisib (BLB) is an oral pan-phosphoinositide 3 kinase (PI3K) inhibitor that selectively targets all class I PI3K isoforms. No prior UPLC-MS/MS method with combined in silico metabolism analysis and green metrics for BLB has been reported, so this research sought to establish a precise, ultra-fast, sustainable, and dependable UPLC-MS/MS approach for estimating BLB in the matrix of human liver microsomes (HLMs), which is employed for determining the metabolic stability of BLB. The UPLC-MS/MS method exhibited a good degree of greenness as approved by the ComplexMoGAPI (69.0) and the AGREEprep tool score (0.68). Ripretinib (RPB) was selected as an internal standard (IS) for BLB quantification in the HLMs matrix. The validated method exhibited a linearity over an extensive concentration span of 1 to 4000 ng mL⁻¹. The accuracy and precision of interday and intraday measurements varied from −2.92% and 10.11% and 3.11 and 9.78%, respectively. The MS/MS analysis was performed by employing the positive ESI ionization mode, and chromatography using an Eclipse Plus C8 column with a run time of one minute. BLB had a moderate extraction ratio, with a clearance rate (Cl_int) of 25.15 mL min⁻¹ kg⁻¹ and an in vitro half-life (t_1/2) of 32.24 min. In silico assessments (P450 and DEREK modules) indicate that minor structural changes in the 2-aminopyridine moiety (lability: 58%) and morpholine groups (lability: 42%) during drug design could increase the metabolic stability and safety profile of BLB. The integrated in vitro technique (metabolic incubation) and in silico tools (ADME, DEREK and WhichP450) provide a resource-effective strategy for preliminary metabolic screening and advancing new therapeutic development aimed at enhancing metabolic stability of new BLB derivatives.