Green Analytical Approaches for Electrochemical and UV–Visible Spectrophotometric Determination of Carfilzomib in Pharmaceutical and Biological Samples

ABSTRACT Carfilzomib (CRF), a second‐generation proteasome inhibitor used in the treatment of relapsed or refractory multiple myeloma, requires sensitive and reliable analytical determination due to its rapid elimination. In this study, two complementary methods were developed and validated: an electrochemical method based on a multi‐walled carbon nanotube‐modified glassy carbon electrode (MWCNTs/GCE) and a UV–Visible spectrophotometric method. The electrochemical approach exhibited a linear response (R 2 = 0.995) with low LOD and LOQ values of 0.017 and 0.056 µM, respectively, along with good repeatability (RSD = 2.0%) and reproducibility (RSD = 1.4%). The method was successfully applied to pharmaceutical formulations, human serum, and urine samples with recoveries ranging from 96.16% to 104.82%. The spectrophotometric method showed good linearity (R 2 = 0.998) with an LOD of 7.3 µM and satisfactory precision and accuracy for dosage form analysis. The environmental performance of both methods was assessed using the GEMAM, AGREE, and GAPI tools, confirming their favorable green analytical characteristics. Overall, the electrochemical method offers superior sensitivity for trace analysis, while the spectrophotometric method provides a simple and cost‐effective alternative for routine applications.