Excipients and their role in drug formulation

Excipients are essential ingredients in pharmaceutical formulations - not just inert fillers, but active contributors to how medicines work, stay stable, and are accepted by patients. This chapter introduces the wide range of excipients used in different dosage forms, including tablets, liquids, creams, eye drops, injections, and inhalers. It explains how excipients are chosen based on their function—such as helping a tablet hold together, improving drug solubility, or preventing contamination, and how their properties affect the final product. The chapter also explores new developments, such as stimuli-responsive polymers and co-processed excipients, demonstrating how innovation in excipient design supports improved drug delivery and treatment outcomes. By bridging foundational principles with cutting-edge developments, the chapter positions excipients as key enablers in modern pharmaceutical formulation.