Associations Between Hydrophibically End-Capped Polyethylene Oxide and Water Soluble (β Cyclodextrin Polymers

Implementation of Water-Soluble Cyclodextrin-Based Polymers in Biomedical Applications: How Far are we?

Cyclodextrin-based polymers can be prepared starting from the naturally occurring monomers following green and low-cost procedures. They can be selectively derivatized pre- or post-polymerization allowing to fine-tune functionalities of ad hoc customized polymers. Preparation nowadays has reached the 100 g scale thanks also to the interest of industries in these extremely versatile compounds. During the last 15 years these macromolecules have been the object of intense investigations in view of possible biomedical applications as the ultimate goal and large amounts of scientific data are now available. Compared to their monomeric models, already used in the formulation of various therapeutic agents, they display superior behavior in terms of their solubility in water and solubilizing power towards drugs incompatible with biological fluids. Moreover, they allow the combination of more than one type of therapeutic agent in the polymeric system. In this review we provide a complete state-of-the-art on the knowledge and potentialities of water-soluble cyclodextrin-based polymers as therapeutic agents as well as carrier systems for different types of therapeutics to implement combination therapy. Finally, we give a perspective on their assets for innovation in disease treatment as well as their limits that still need to be addressed. This article is protected by copyright. All rights reserved.

Controlling the Association of Adamantyl-Substituted Poly{N-[tris(hydroxymethyl)methyl]acrylamide} and aβ-Cyclodextrin/Epichlorohydrin Polymer by a Small Drug Molecule – Naproxen

Two polymeric substances, a poly{N-[tris(hydroxymethyl)methyl]acrylamide} (THMMA) substituted with adamantyl moieties and a beta-cyclodextrin/epichlorohydrin polycondensate, formed a host-guest type complex, which resulted in the gel formation upon mixing of these two compounds at appropriate conditions. Introduction of a drug molecule, i.e., naproxen, that was able to fill the beta-cyclodextrin cavities, thus expulsing adamantyl moieties, led to disruption of such association and inhibition of gel formation. The conditions required for the association of the two polymeric components and formation of the gel, as well as the dynamics of its inhibition by addition of naproxen was established. The procedure of using solutions of two associating polymers and an appropriate drug competitor can be used at targeted viscosupplementation.

High-performance liquid chromatographic study of the interactions between immobilized beta-cyclodextrin polymers and hydrophobically end-capped polyethylene glycols

The formation of inclusion complexes between polyethylene glycols (PEGs) bearing hydrophobic ends (naphtyl and phenyladamantyl) and beta-cyclodextrin polymers (poly beta-CD) immobilized onto silica particles was studied by high-performance liquid chromatography (HPLC). It was shown that hydrophobic interactions were involved in the retention mechanism of these compounds, since retention volumes decreased when organic solvents were added to the mobile phase while it was the contrary in the presence of salts. Moreover, the association could be reversed by adding a competitor (hydroxypropyl beta-cyclodextrin) to the mobile phase. A theoretical model permitted the evaluation of affinity constants of 1:1 complexes formed between the modified PEGs and the immobilized poly beta-CD which depended on the type of hydrophobic groups grafted to the PEG.