Onivyde® (irinotecan liposomal injection) is a pivotal treatment for metastatic pancreatic cancer, designed for enhanced stability and improved tumor accumulation via the enhanced permeability and retention (EPR) effect. As generic versions emerge with patent expiration approaching, a reliable in vitro release test (IVRT) is critical to ensure product quality and bioequivalence. This study develops an optimized IVRT for Onivyde® using the Agilent NanoDis® system, which integrates tangential flow filtration and standard dissolution equipment. Key parameters, including filter material, molecular weight cut-offs (MWCOs), medium composition and pH, and paddle speed, were systematically evaluated to refine the method. The final method effectively identified variations in formulations subjected to stress conditions, assessed batch consistency, and differentiate different mixtures of liposomal irinotecan and free drug. This optimized IVRT can support quality control, regulatory approval, and bioequivalence assessment of generic Onivyde® formulations, ensuring consistent therapeutic performance.