Integrated analytical quality by design enabled stability-indicating LC-MS method for cabazitaxel: forced degradation...

Cabazitaxel (CBZ) is a second-generation semi-synthetic taxane used for metastatic castration-resistant prostate cancer therapy. This study aims to introduce a novel, streamlined analytical workflow for CBZ that bridges a critical gap in current literature by uniquely integrating Analytical Quality by Design (AQbD) chromatographic optimization, stability-indicating forced degradation, LC-MS degradation-product profiling, in silico absorption, distribution, metabolism, excretion, and toxicity (ADMET) evaluation, and a multi-metric greenness assessment into a single, comprehensive pipeline. Separation was achieved on a Phenomenex Luna C8 column using 0.1% acetic acid in water : acetonitrile (38 : 62, v/v) at 0.8 mL min^-1 with UV detection at 229 nm. A Box-Behnken design was used to optimize critical method parameters, under which CBZ was eluted at approximately 12 min. Forced degradation included acidic hydrolysis (0.1 N HCl, 80 °C, 30 min), alkaline hydrolysis (0.01 N NaOH, 50 °C, 30 min), oxidation (3% H₂O₂, 80 °C, 30 min), dry heat (80 °C, 5 days), and ICH Q1B photolysis. The greatest degradation occurred under alkaline (33.33%), photolytic (32.55%), and oxidative (29.92%) stress. Four major degradation products (DPs) were tentatively assigned based on LC-MS data at m/z 735.74, 600.85, 572.77, and 775.73. In silico ADMET profiling for CBZ and its DPs showed that DP2 crosses the blood-brain barrier. The method was linear over 0.06-270 µg mL^-1 (r² = 0.9998), with LOD and LOQ values of 0.02 and 0.06 µg mL^-1, respectively; recovery was 98.84-99.69%, and precision was <2% RSD. The method was applied to marketed injections, giving assay recoveries of 98.47-98.89%. Greenness/applicability assessment yielded an Eco-Scale score of 90, AGREE (0.61), BAGI (80.0), RAPI (80.0) and AGSA (84.72); GAPI identified workflow-specific environmental trade-offs, while Mosaic-WAC gave an overall score of 82.3. These complementary metrics support favorable overall analytical performance. Overall, the developed integrated approach provides a reliable platform for CBZ quality control, stability assessment, and degradation profiling.