Biocompatibility of cucurbit[ <i>n</i> ]urils

This review considers the biological properties of nitrogen-containing macrocyclic glycoluryl derivatives – cucurbit[n]urils (CB[n]). Currently, the use of biomaterials that come into contact with the internal environment of the body is widespread in medicine. Of particular interest is the possibility of giving biocompatible biomaterials new properties by impregnating them with various chemical compounds, fine-tuning these properties for each specific task. One example of such customization is the use of cucurbit[n]urils. Cucurbit[n]urils are a class of macrocyclic organic compounds that are hollow molecules in a “barrel” shape. Their structure is formed from glycoluryl (a urea derivative) and formaldehyde linked into a cyclic framework. The cavity of cucurbit[n]urils is hydrophobic and the entrances are hydrophilic, allowing them to “capture” and retain guest molecules. They are chemically stable, resistant to acids and high temperatures, and able to select guest molecules based on their size, shape and chemical nature. The presented review focuses on the properties of cucurbit[n]urils, their biological activity, in vitro and in vivo toxicity, their potential use in medicine as antidotes, for disease diagnosis, and targeted drug delivery. General information about cucurbit[n]urils as a basis for creating biomaterials for medical purposes and targeted drug delivery agents is considered. Generalized experimental data on the toxicity of cucurbit[n]urils both in vitro and in vivo are overviewed.