Continuous Manufacturing in Solid Dosage Forms: Quality and Regulatory Perspective

Continuous manufacturing (CM) has emerged as one of the most important paradigm shifts in the pharmaceutical industry, particularly for small-molecule oral solid dosage (OSD) forms where traditional batch processes have dominated for decades. Instead of producing a finite number of units in isolated equipment trains, CM operates by feeding materials and withdrawing finished product simultaneously in a coordinated, often highly automated, production line. This architecture enables richer process understanding, tighter control, and opportunities for real-time release testing (RTRT), but it also challenges legacy concepts of batch definition, validation, and regulatory oversight.This review consolidates contemporary knowledge on CM in solid dosage forms with a dual focus on quality science and the evolving regulatory landscape. It begins by outlining the fundamentals of OSD CM architectures and enabling technologies, then discusses the role of Quality by Design (QbD), Process Analytical Technology (PAT), and control strategies in assuring critical quality attributes (CQAs). Subsequent sections examine international and regional guidance, regulatory experience, representative case studies, and open implementation challenges, concluding with perspectives on digitalization, Pharma 4.0, and future regulatory convergence.