Validated UPLC-DAD Method for Quantification of Pazopanib in Human Urine and Detection of Degradation Products by UPLC-MS

Introduction/Objective: Pazopanib is a key targeted therapy for advanced renal cell carcinoma, yet data on its quantification and degradation behavior in urine are limited. This study aimed to develop and validate a rapid UPLC-DAD method for pazopanib determination in human urine and to investigate its degradation profile using UPLC-MS/MS. Methods: A UPLC-DAD method was optimized using a ZORBAX Eclipse Plus C18 column with isocratic elution and erlotinib as the internal standard. The method was validated according to ICH guidelines. Forced-degradation studies under acidic, basic, oxidative, thermal, and photolytic conditions were conducted and analyzed by LC-MS/MS to characterize degradation behavior. Results: The method exhibited excellent linearity (0.5–20 μg/mL, R² = 0.9995), low LOD/LOQ (0.0832/0.2521 μg/mL), and high precision and recovery (97.32–100.21%). Chromatographic separation of pazopanib and the internal standard was achieved within 4 minutes. Pazopanib remained stable under acidic, basic, thermal, and photolytic stress but showed significant degradation under oxidative conditions. Discussion: The validated method provides a fast, sensitive, and reliable approach for paz-opanib quantification in urine. The degradation findings highlight the drug’s overall stability and susceptibility to oxidative stress, offering insights relevant to sample handling, storage, and clinical monitoring. Conclusion: A simple and robust UPLC-DAD method was developed for pazopanib quantification in human urine and supported by degradation profiling using LC-MS/MS. This approach is suitable for therapeutic drug monitoring and enhances understanding of pazo-panib’s stability characteristics.