Experimental and computational studies on possibility of using glucose diazacrown cryptand as a carrier for anticancer drugs busulfan and lomustine

Drug carriers play a very important role in pharmacy, especially in cancer therapy. Most drugs used in the treatment of cancer are characterized by poor solubility in water and lack of selectivity in their toxic effects on normal and cancer cells. Administration of the drug in the form of a complex with an appropriately selected carrier can significantly improve its therapeutic effect and reduce side effects. In this study, the possibility of using the cryptand L1, containing two diazacrown ethers and two saccharide groups, as a potential drug carrier is investigated. In order to determine whether it can form complexes with drugs, the cryptand L1 and its complexes with two anticancer drugs, busulfan (BSF) and lomustine (CCNU), were synthesized. Their selected structural and energetic properties were investigated using both experimental and computational methods. Additionally, water solubility and cytotoxicity tests were performed for all compounds. The measured 1H NMR spectra confirm that L1 forms complexes L1:BSF and L1:CCNU, the solubility of which in water appears to be much higher than that of the pure drugs. The results of DFT calculations made in water described with the implicit solvent model confirm high stability of L1:BSF and L1:CCNU and indicate that L1 forms with the drugs mainly non-inclusion complexes. However, additional tests with 20 H2O molecules explicitly included in the model suggest that both inclusion and non-inclusion forms can occur in a real solution. Cytotoxicity studies show that the macrocycle L1 is non-toxic towards both normal and cancer cells, and its complexes with drugs show greater selectivity towards cancer cells. Interestingly, while the cytotoxicity of the L1:BSF complex is stronger than that of pure BSF, the relationship is opposite in the case of L1:CCNU and CCNU. Therefore, L1 can be considered as a potential drug carrier, especially for those drugs that have weak activity on cancer cells.

In Search of the Most Stable Molecular Configuration of Heptakis(2,6-O-dimethyl)-β-cyclodextrin and Its Complex with Mianserin: A Comparison of the B3LYP-GD2 and M062X-GD3 Results

Cyclodextrins are well known for their ability to form stable, highly soluble complexes with various substances, which makes them widely used as excipients in food, cosmetics, and pharmaceuticals. In this work, properties of heptakis(2,6-O-dimethyl)-β-cyclodextrin (DM-β-CD) in vacuo and in water, as well as its ability to bind the antidepressant drug mianserin (MIA) in aqueous solution, are investigated computationally. The results are shown to depend strongly on the density functional theory (DFT) applied. The most stable conformers of DM-β-CD found with the B3LYP-GD2 method differ from these indicated by M062X-GD3 and other functionals. According to the latter, two crystal structures, ZULQAY and BOYFOK03, optimized in vacuo and in water, respectively, have the lowest energy. Both the B3LYP-GD2 and M062X-GD3 results show that all tested inclusion and noninclusion complexes of MIA:DM-β-CD in stoichiometry 1:1 are stable in water. However, the structures and their energetic properties obtained with each method differ: in the most stable configurations, different aromatic rings of MIA are embedded inside DM-β-CD, and the corresponding complexation energies (calculated with the 6-31++G(d,p) basis set and corrected for the basis set superposition error) are -29.6 (B3LYP-GD2) and -23.9 (M062X-GD3) kcal/mol. The NMR spectra of DM-β-CD and MIA:DM-β-CD are also compared.

Thermodynamic Studies of Interactions between Sertraline Hydrochloride and Randomly Methylated β-Cyclodextrin Molecules Supported by Circular Dichroism Spectroscopy and Molecular Docking Results

The interaction between sertraline hydrochloride (SRT) and randomly methylated β-cyclodextrin (RMβCD) molecules have been investigated at 298.15 K under atmospheric pressure. The method used-Isothermal Titration Calorimetry (ITC) enabled to determine values of the thermodynamic functions like the enthalpy (ΔH), the entropy (ΔS) and the Gibbs free energy (ΔG) of binding for the examined system. Moreover, the stoichiometry coefficient of binding (n) and binding/association constant (K) value have been calculated from the experimental results. The obtained outcome was compared with the data from the literature for other non-ionic βCD derivatives interacting with SRT and the enthalpy-entropy compensation were observed and interpreted. Furthermore, the connection of RMβCD with SRT was characterized by circular dichroism spectroscopy (CD) and complexes of βCD derivatives with SRT were characterized through the computational studies with the use of molecular docking (MD).

The Interaction of Heptakis (2,6-di-O-Methyl)-β-cyclodextrin with Mianserin Hydrochloride and Its Influence on the Drug Toxicity

One tetracyclic antidepressant, mianserin hydrochloride (MIA), has quite significant side effects on a patients’ health. Cyclodextrins, which are most commonly used to reduce the undesirable features of contained drugs within their hydrophobic interior, also have the potential to alter the toxic behavior of the drug. The present paper contains investigations and the characteristics of interaction mechanisms for MIA and the heptakis (2,6-di-O-methyl)-β-cyclodextrin (DM-β-CD) system, and evaluated the effects of the complexation on MIA cytotoxicity. In order to assess whether there was an interaction between MIA and DM-β-CD molecules, isothermal titration calorimetry (ITC) have been chosen. Electrospray ionization mass spectrometry (ESI-MS) helped to establish the complex stoichiometry, and circular dichroism spectroscopy was used to describe the process of complex formation. In order to make a wider interpretative perspective, the molecular docking results have been performed. The viability of Chinese hamster cells were investigated in the presence of DM-β-CD and its complexes with MIA in order to estimate the cytotoxicity of the drug and the conjugate with the chosen cyclodextrin. The viability of B14 cells treated with MIA+DM-β-CD is lower (the toxicity is higher) than with MIA alone, and no protective effects have been observed for complexes of MIA with DM-β-CD in any ratio.

Innovative Organic Electroluminescent Materials with a Doublet Ground State: A Theoretical Investigation

The displaced and distorted harmonic oscillator model, which has been proven to be appropriate in calculating vibronic spectra, is employed to treat the emission spectrum of title molecules in combination with a thermal vibration correlation function. The calculated results indicate that the main peak of the emission spectrum is visibly impacted by the normal modes with lower frequencies and that the shoulder peak is originated from the middle-frequency modes. On the level of time-dependent density functional theory (TDDFT), the calculated fluorescence lifetimes of TTM-3NCz and TTM-3PCz are 22.1 and 26.0 ns, respectively, which happen to coincide with the observed values of TTM-3NCz (17.2 ns) and TTM-3PCz (21.2 ns). The above data indicate that both the calculated radiative decay rates are reasonable at room temperature. Furthermore, we investigate the influence of the Duschinsky effect on the fluorescence quantum efficiency (FQE). When it is considered, the predicted FQE of the TTM-3NCz molecule is only 0.11%, and the observed value (49% in toluene) deviates significantly. If we ignore the Duschinsky effect, the FQE of TTM-3NCz increases dramatically to 41.8%. For the TTM-3PCz molecule (the FQE is 46% in toluene), the calculated FQE is 0.042% with the Duschinsky effect and increases to 45.2% without the Duschinsky effect. This phenomenon might be related to external factors and the nature of the TDDFT only considering a single configuration. In addition, the fluorescent properties of the fluorinated TTM-3NCz molecules are studied predictably. The obtained results show that the perfluorinated TTM-3NCz shows better luminous performance due to larger oscillator strength. Finally, the dimers, which are composed of both single title molecules, are explored theoretically to determine how they impact the fluorescent property; however, the effect can be nearly eliminated because of the small binding energies.