Quality By Design (QbD) in Pharmaceutical Formulation Development: A Systematic Review

Quality by Design (QbD) is a regulatory-endorsed, systematic, and science-based approach that emphasizes comprehensive process understanding and risk-based control strategies to ensure consistent pharmaceutical product quality. Unlike conventional development paradigms that rely heavily on end-product testing, QbD embeds quality within formulation and process design from the earliest stages of development. This systematic review critically evaluates the application of QbD principles in pharmaceutical formulation development and assesses their influence on product quality, process robustness, manufacturing efficiency, and regulatory compliance throughout the product lifecycle. A comprehensive literature search was conducted in PubMed, Google Scholar, ScienceDirect, SpringerLink, and Wiley Online Library in accordance with PRISMA guidelines. Peer-reviewed articles published between 2010 and 2025 that reported the implementation of QbD tools in formulation and process development were included. The review highlights the extensive use of core QbD elements, including Quality Target Product Profile (QTPP), identification of Critical Quality Attributes (CQAs), risk assessment methodologies, Design of Experiments (DoE), and Process Analytical Technology (PAT), across diverse dosage forms such as solid oral dosage forms, modified-release systems, nanoformulations, and advanced drug delivery platforms. The findings demonstrate that QbD-based development enhances formulation robustness, minimizes batch-to-batch variability, improves process understanding, and supports regulatory flexibility through the establishment of design space and risk-based control strategies. Despite challenges associated with increased initial resource requirements, data complexity, and the need for specialized expertise, QbD provides a robust framework for continuous improvement, efficient scale-up, and effective lifecycle management. Overall, the adoption of QbD aligns with global regulatory expectations and represents a critical shift toward more reliable, efficient, and patient-centric pharmaceutical development. Among the included studies, approximately 70–80% employed Design of Experiments (DoE) as a core QbD tool, while 45–60% reported establishment of design space. Advanced tools such as Process Analytical Technology and Real-Time Release Testing were applied in nearly 20–30% of studies, reflecting gradual industrial adoption. Furthermore, the review highlights the growing relevance of QbD in ANDA and NDA submissions, where risk-based development supports regulatory flexibility and lifecycle management