A recent update of water-soluble polymers in cyclodextrin-based formulations for mucosal drug delivery.

Cyclodextrins (CDs) play a crucial role in pharmaceutical formulations due to their unique ability to form inclusion complexes with a wide range of lipophilic drugs. Ternary complexes comprising CD, water-soluble polymer, and drug molecule have emerged as promising multicomponent to the challenges associated with poorly water-soluble drugs. The addition of water-soluble polymer as a ternary component often reduces the amount of CD required to form an inclusion complex thereby decreasing formulation bulk and toxicity. This review outlines the physicochemical properties of CDs and the formation of their inclusion complexes, as well as methods to enhance the complexation efficiency of drug/CD complexes. Additionally, it explores the classification and mucoadhesive properties of water-soluble polymers, and their mechanisms of mucoadhesion on mucosal membranes. The presence of small amounts of water-soluble polymers has been demonstrated to synergistically improve the complexation efficiency of drug/CD complexes. Recent advancements in modified CD-polymer conjugates and the use of water-soluble polymers in CD-based formulations, and their applications across various routes of administration are discussed, highlighting the potential of these ternary complexes as innovative platforms for drug delivery and therapeutic applications.