PEG-Modified tert-Octylcalix[8]arenes as Drug Delivery Nanocarriers of Silibinin

Water-Soluble Polyglycidol-Grafted Ladder Calix Resorcinarene Oligomers with Open Chain and Cyclic Topologies: Synthesis, Characteristics, and Biological Evaluation

Ladder oligomers containing calixarene skeletons in the main chain-calix[4]resorcinarene (CRA) ladder macromolecules with open chain and cyclic macromolecules with double ring-like (Noria-type) topologies-bring particular research attention as functional materials with various applications. However, there is still a remarkable lack of studies into the synthesis of fully water-soluble derivatives of these interesting macromolecules. Research on this topic would allow their bio-based research and application niche to be at least revealed. In the present study, a strategy for the synthesis of water-soluble polyglycidol-derivatized calix resorcinarene ladder oligomers with open chain and cyclic structures is introduced. A grafting from approach was used to build branched or linear polyglycidol chains from the ladder scaffolds. The novel structures were synthesized in quantitative yields and fully characterized by NMR, FTIR and UV-vis spectroscopy, gel permeation chromatography, MALDI-TOF mass spectrometry, analytical ultracentrifugation, and static light scattering to obtain the molar mass characteristics and composition. The biocompatibility and toxicity of the two polyglycidol-derivatized oligomers were investigated and the concentration dependence of the survival of three cell lines of human origin determined. The selective apoptosis effect at relatively low dissolve concentrations toward two kinds of cancerous cell lines was found.

Macrocycle-Based Supramolecular Drug Delivery Systems: A Concise Review

Efficient delivery of therapeutic agents to the lesion site or specific cells is an important way to achieve "toxicity reduction and efficacy enhancement". Macrocycles have always provided many novel ideas for drug or gene loading and delivery processes. Specifically, macrocycles represented by crown ethers, cyclodextrins, cucurbit[n]urils, calix[n]arenes, and pillar[n]arenes have unique properties, which are different cavity structures, good biocompatibility, and good stability. Benefited from these diverse properties, a variety of supramolecular drug delivery systems can be designed and constructed to effectively improve the physical and chemical properties of guest molecules as needed. This review provides an outlook on the current application status and main limitations of macrocycles in supramolecular drug delivery systems.

Applications of supramolecular assemblies in drug delivery and photodynamic therapy

One of the world's serious health challenges is cancer. Anti-cancer agents delivered to normal cells and tissues pose several problems and challenges. In this connection, photodynamic therapy (PDT) is a minimally invasive therapeutic technique used for selectively destroying malignant cells while sparing the normal tissues. Development in photosensitisers (PSs) and light sources have to be made for PDT as a first option treatment for patients. In the pursuit of developing new attractive molecules and their formulations for PDT, researchers are working on developing such type of PSs that perform better than those being currently used. For the widespread clinical utilization of PDT, effective PSs are of particular importance. Host-guest interactions based on nanographene assemblies such as functionalized hexa-cata-hexabenzocoronenes, hexa-peri-hexabenzocoronenes and coronene have attracted increasing attention owing to less complicated synthetic steps and purification processes (gel permeation chromatography) during fabrication. Noncovalent interactions provide easy and facile approaches for building supramolecular PSs and enable them to have sensitive and controllable photoactivities, which are important for maximizing photodynamic effects and minimizing side effects. Various versatile supramolecular assemblies based on cyclodextrins, cucurbiturils, calixarenes, porphyrins and pillararenes have been designed in order to make PDT an effective therapeutic technique for curing cancer and tumours. The supramolecular assemblies of porphyrins display efficient electron transfer and fluorescence for use in bioimaging and PDT. The multifunctionalization of supramolecular assemblies is used for designing biomedically active PSs, which are helpful in PDT. It is anticipated that the development of these functionalized supramolecular assemblies will provide more fascinating advances in PDT and will dramatically expand the potential and possibilities in cancer treatments.

Separation performance of the calix[8]arene functionalized with polyethylene glycol units for capillary gas chromatography

In this paper, an amphiphilic calix[8]arene with polyethylene glycol unit branches (C8A-PEG) was synthesized and applied for capillary gas chromatography (GC). The C8A-PEG was coated on the inner wall of a capillary column by a static method with the column efficiency of 3165 plates/m and polar nature. As demonstrated, the C8A-PEG column has excellent physicochemical properties and separation performance since it has π-electron-rich 3D cavity which combines with polar PEG units. Compared with two columns corresponding to the construction units C8A and PEG, the C8A-PEG column shows distinctly advantageous performance for the mixture of 22 components with diverse types. Impressively, it shows satisfactory resolution for positional isomers and cis-/trans- isomers, especially the challenging isomers of toluidine and dimethylaniline. The outstanding distinguishing capability of the C8A-PEG stationary phase is mainly attributed to the abundant molecular recognition interactions, including van der Waals, dipole-dipole, H-bonding and π-π stacking interactions. This work has proved that the new GC stationary phases constructed by different units can complement each other's advantages, improve their physicochemical properties and separation performance, and have broad application prospects in chromatographic analysis.

Polymers Enhancing Bioavailability in Drug Delivery

A drug's bioavailability, i.e., the extent to and rate at which it enters the systemic circulation, thus accessing the site of action, is largely determined by the properties of the drug [...].