Synthesis of Novel Supramolecular Assemblies Based on Hyaluronic Acid Derivatives Bearing Bivalent β-Cyclodextrin and Adamantane Moieties

Abstract

New supramolecular assemblies based on hyaluronic acid stabilized by divalent -cyclodextrin/ adamantane ( -CD/AD) complexes were synthesized with the aim to compare their viscoelastic behavior in aqueous medium with systems resulting from monovalent complexes. For this purpose, dimers of AD and -CD to be coupled to hyaluronic acid were prepared by multistep chemical synthetic pathways. Investigation of the complexation properties of these dimers by isothermal titration calorimetry (ITC) experiments revealed a pronounced increase of the stability constant. These results can be attributed to divalency as suggested by the value of the complexation enthalpy (∆H 0 ) which is twice that of the monovalent complex, in agreement with literature data. Nevertheless, a decrease of the complexation properties of these dimers when fixed on the polysaccharide backbone was observed as a result of an unfavorable entropy of binding. The viscoelastic properties of the supramolecular assemblies were examined by dynamic rheological measurements, showing different behaviors related to the nature and the energy of the interchain physical junctions.

Poly-cyclodextrin and poly-paclitaxel nano-assembly for anticancer therapy

“…On average, more than 90% of monomeric PTX/CD complexes dissociated after 100 ns, whereas PTX/pCD and pPTX/pCD displayed only 20-30% PTX/CD pair dissociations after the same time. These data support the conclusion that the stability of the nanoassembly results from the multiplicity of the PTX/CD inclusion complexes formed between the two polymer conjugates 32,33 .…”

Protein‐Release Behavior of Self‐Assembled PEG–β‐Cyclodextrin/PEG–Cholesterol Hydrogels

“…[12][13][14][15] A great variety of physically crosslinked hydrogels have been reported, which are based on ionic interactions, [16,17] hydrophobic interactions, [18][19][20] hydrogen bonds, [21,22] crystallinity, [23] stereocomplex formation, [24][25][26][27] or specific biomimetic interactions. [28][29][30] We and others recently reported on selfassembling hydrogel systems, [31][32][33][34][35][36][37] in which physical crosslinking is established by inclusion complex formation between b-cyclodextrin (bCD) and a complementary low molecular weight guest molecule. The cyclic oligosaccharide bCD is composed of 7 glucopyranose units that are joined by a-1,4-glucosidic linkages.…”

“…[38] Driven by hydrophobic and van der Waals interactions, the relatively hydrophobic pocket of bCD serves as a reversible binding site for a wide range of lipophilic molecules (e.g., adamantane and cholesterol). [39][40][41] Reversible hydrogel systems, for example, those composed of adamantane-and bCD-grafted chitosan [42] or hyaluronic acid [33,43] have been described in the literature. Also, stimuli-responsive gels were formed after combining poly(acrylamide) derivatized with either bCD or aromatic guest molecules.…”

Polymers Containing Covalently Bonded and Supramolecularly Attached Cyclodextrins as Side Groups

“…As model system, a mixture of two hyaluronic acid derivatives functionalized either with bCD or adamantly residues was chosen [29,65]. Above the overlap concentration it was found that these polymer systems generate parallel strands of contrarily derivatized polymers, denoted as railway complexes.…”