Host-guest inclusion complex between β-cyclodextrin and paeonol: A theoretical approach

Enhancing the Drug-Like Profile of a Potent Peptide PACE4 Inhibitor by the Formation of a Host-Guest Inclusion Complex with β-Cyclodextrin

The enzyme PACE4 has been validated as a promising therapeutic target to expand the range of prostate cancer (PCa) treatments. In recent years, we have developed a potent peptidomimetic inhibitor, namely, compound C23 (Ac-(DLeu)LLLRVK-4-amidinobenzylamide). Like many peptides, C23 suffers from an unfavorable drug-like profile which, despite our efforts, has not yet benefited from the usual SAR studies. Hence, we turned our attention toward a novel formulation strategy, i.e., the use of cyclodextrins (CDs). CDs can benefit compounds through the formation of "host-guest" complexes, shielding the guest from degradation and enhancing biological survival. In this study, a series of βCD-C23 complexes have been generated and their properties evaluated, including potency toward the enzyme in vitro, a cell-based proliferation assay, and stability in plasma. As a result, a new βCD-formulated lead compound has been identified, which, in addition to being more soluble and more potent, also showed an improved stability profile.

Synthesis and Characterization of an Inclusion Complex of dl-Aminoglutethimide with β-Cyclodextrin and Its Innovative Application in a Biological System: Computational and Experimental Investigations

Our present study intended to investigate the encapsulation of DL-AGT within the lipophilic cavity of a β-CD molecule. The consequential inclusion system was characterized by UV-visible spectroscopy and ¹H NMR, PXRD, SEM, and FT-IR studies. Molecular docking was performed for the inclusion complex to discover the most proper orientation, and it was seen that the drug DL-AGT fits into the cavity of β-CD in a 1:1 ratio, which was also confirmed from the Job plot. Furthermore, a comparison was done on the basis of cell viability between the drug and its inclusion complex.

Electrospun Polymer-Free Nanofibers Incorporating Hydroxypropyl-β-cyclodextrin/Difenoconazole via Supramolecular Assembly for Antifungal Activity

In this study, flexible and self-standing hydroxypropyl-β-cyclodextrin/difenoconazole inclusion complex (HPβCD/DZ-IC) nanofibers were prepared by polymer-free electrospinning, which exhibited potential to be a new fast-dissolving pesticide formulation. Scanning electron microscopy and optical microscopy were applied to evaluate the morphology of nanofibers, which showed that the resulting HPβCD/DZ-IC nanofibers were bead-free and uniform. In addition, the proton nuclear magnetic resonance (¹H NMR) spectrum suggested a stoichiometric ratio of 1:0.9 (HPβCD/DZ). Other characterization methods, such as UV-vis absorption, fluorescence spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA), were applied in this study. On the one hand, UV-vis absorption, fluorescence spectroscopy, FT-IR, XRD, and TGA provided useful information for the successful formation of an inclusion complex; on the other hand, the results of TGA indicated the thermal stability of DZ was enhanced after the formation of inclusion complexes. Besides, the phase solubility test could explain the increased water solubility of the nanofibers of inclusion complexes formed by DZ and HPβCD. The results of molecular docking studies demonstrated the most favorable binding interactions when HPβCD combined with DZ. The dissolution test and the antifungal performance test exhibited the characteristics of fast dissolution and the excellent antifungal performance of HPβCD/DZ-IC nanofibers, respectively.

Physical Characterization of Inclusion Complexes of Triphenyl Phosphate and Cyclodextrins in Solution

The goal of this work is to provide physical insights into the formation and stability of inclusion complexes (ICs) in aqueous solution between cyclodextrins (CDs) and a common flame retardant, triphenyl phosphate (TPP). Quantum chemistry calculations reveal the possible energetically favorable geometries of TPP in their 1:1 IC form with α-, β-, and γ-CDs as well as their associated complexation, conformational, and interaction energies. High-resolution mass spectrometry (MS) and tandem MS were used with electrospray ionization to study the soluble ICs formed between TPP and CDs. Successful formation of TPP ICs with both β- and γ-CD in solution was detected in the ratio of 1:1 using high-resolution MS in the positive ion mode. Collision-induced dissociation confirmed the formation of TPP ICs with β- and γ-CDs by generating two product ions, TPP and β- or γ-CD, in both cases. Although quantum chemistry calculations suggest that IC formation with α-CD is energetically possible, an IC with α-CD is not observed in aqueous solution using MS, which aligns with what we also previously observed in the solid state. Since TPP forms stable ICs with β- and γ-CDs both in the solid state and in solution suggests that complexation could be a safer alternative than applying TPP directly to a substrate. In addition, complexation with CDs in solution also opens up new processing methods to create flame-retardant fabrics and foams with TPP.

Interaction of β-cyclodextrin as catalyst with acetophenone in asymmetric reaction: a theoretical survey

The asymmetric reduction of acetophenone with sodium borohydride in the presence of β-cyclodextrin (β-CD) as catalyst can improve selectivity and yield. The interaction between acetophenone and β-CD plays an important role for the reduction of acetophenone. This work studies the reaction of acetophenone in the presence of β-CD using density functional theory (DFT) method. Energy is investigated to find out the lowest energy of two possible complexation models. The geometrical structure confirms that acetophenone inserts into the cavity mainly from the secondary hydroxyl side. Hydrogen bonds are researched on the basis of natural bonding orbital (NBO) analysis, the results confirm the donor-acceptor interactions of complex. Mülliken charge and frontier orbital are employed for revealing the electronic transfer. In addition, (13)C nuclear magnetic resonance ((13)CNMR) spectroscopy shows that the active site concentrates on the carbon atom of carbonyl group. The probable catalytic mechanism of β-CD is discussed in terms of the calculated parameters.