Solid-state interactions of calixarenes with biorelevant molecules

Abstract

Among all crystalline complexes of calix-type calix[n]arenes those with organic molecules which are biologically relevant are especially of interest due to their potential medical and pharmaceutical applications. The co-crystallization of drugs with water-soluble calixarenes offers the opportunity to modify chemical and physical properties of APIs (active pharmaceutical ingredients) and to control drug conformation. Such co-crystallization can improve solubility, bioavailability and stability of pharmaceutically active molecules and/or eliminate polymorphism. In this article the solid-state interactions between calixarene hosts and biologically relevant guest molecules are summarized for the currently available structures solved by single-crystal X-ray crystallography.

Reversible Nanoparticle–Micelle Transformation of Ionic Liquid–Sulfonatocalix[6]arene Aggregates

“…11,12 Because of their flexible π-electron-rich cavity and negative charge, 4-sulfonatocalix[n]arenes (SCXn) are particularly beneficial building elements for the creation of diverse nanostructures. [13][14][15] The role of SCXn in the design of fluorescent sensing systems, pesticide detoxification, drug delivery, 16 biochemistry, 17,18 crystal engineering 13,19 and supramolecular polymerization 20 has been reviewed. In contrast to cyclodextrins or cucurbiturils, which induces the dissociation of aggregates by host-guest complexation, 21 the binding to SCXn promotes the aggregation of aromatic or amphiphilic compounds.…”

Complexation study and spectrofluorometric determination of the binding constant for diquat and p-sulfonatocalix[4]arene

“…The interactions between diquat (DQ) and p-sulfonatocalix [4]arene (C4S) were studied in an aqueous solution as a function of the ionic strength. Evidence for the formation of a complex between DQ and C4S was obtained using fluorescence measurements, while the stoichiometry of the complex was confirmed as 1:1 for DQ/C4S using UVevis spectroscopy.…”

“…1(a), p-sulfonatocalix [4]arene, C4S) are an important class of calix[n]arene, which are water soluble and have the ability to bind with a wide range of metal cations, organic ammonium cations and neutral organic molecules. 2,3 This diverse supramolecular chemistry has led to their application in several fields including pharmaceutical chemistry, 4 catalysis 5 and sensors.…”

“…1(a), p-sulfonatocalix [4]arene, C4S) are an important class of calix[n]arene, which are water soluble and have the ability to bind with a wide range of metal cations, organic ammonium cations and neutral organic molecules. 2,3 This diverse supramolecular chemistry has led to their application in several fields including pharmaceutical chemistry, 4 catalysis 5 and sensors. 6 The ability of p-sulfonatocalix [n]arenes to bind with viologens was first reported by Kaifer et al 7 More recently, it has been shown that the strong electrostatic interaction of the cationic viologen with the anionic calix[n]arene can be enhanced by the pep interactions between the host cavity and the guest molecule.…”

“…9e14 Moreover, viologens are commonly used as herbicides and are potentially fatal to human health. 15 Interestingly, a number of recent studies 16,17 have investigated the potential of employing the complexation of p-sulfonatocalix [4]arenes with viologens as a therapeutic agent for methylviologen poisoning. The likelihood of medicinal applications of p-sulfonatocalix [4]arenes has increased as preliminary studies would indicate that C4S has a low toxicity.…”