Purpose <p>Nanomedicines such as PEGylated liposomal doxorubicin are non-biological complex drugs whose quality and therapeutic performance are governed by intricate nanoparticle characteristics. Regulatory agencies worldwide consistently emphasize comprehensive physicochemical characterization as a prerequisite for assuring quality, safety, and efficacy of complex generic products. This study aimed to establish a regulatory-aligned critical quality attribute (CQA) framework for nanomedicines by integrating guidance from U.S., European, Japanese, and Korean regulatory authorities.</p> Methods <p>PEGylated liposomal doxorubicin was selected as a representative case study. Regulatory guidance documents from multiple agencies were systematically reviewed to identify nanoparticle attributes critical to product performance. The reference listed drug, Doxil^® (marketed as Caelyx^® in Europe and Korea), was comprehensively characterized under varying dispersion media, pH, ionic strength, and temperature conditions using standardized and reproducible analytical methods to assess structural and functional attributes of the liposomal carrier.</p> Results <p>Cross-agency regulatory perspectives converged on a set of CQAs encompassing size-related properties, surface characteristics, drug encapsulation, and stability-related parameters. Experimental characterization demonstrated that these attributes were sensitive to environmental conditions and directly reflected the structural integrity and functional performance of the liposomal formulation.</p> Conclusion <p>This study proposes a scientifically grounded CQA reference framework that links nanoparticle structure to performance while aligning with multi-agency regulatory expectations. The framework provides a transferable analytical approach to support the development, evaluation, and regulatory assessment of complex generic nanomedicines.</p>