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Open AccessArticle

17-β-Estradiol—β-Cyclodextrin Complex as Solid: Synthesis, Structural and Physicochemical Characterization

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Marta Katarzyna Dudek

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Monika Zielińska-Pisklak

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Dariusz Maciej Pisklak

Molecules 2023, 28(9), 3747; https://doi.org/10.3390/molecules28093747 - 26 Apr 2023

Viewed by 526

Abstract

17-β-estradiol (EST) is the most potent form of naturally occurring estrogens; therefore, it has found a wide pharmaceutical application. The major problem associated with the use of EST is its very low water solubility, resulting in poor oral bioavailability. To overcome this drawback, [...] Read more.

17-β-estradiol (EST) is the most potent form of naturally occurring estrogens; therefore, it has found a wide pharmaceutical application. The major problem associated with the use of EST is its very low water solubility, resulting in poor oral bioavailability. To overcome this drawback, a complexation with cyclodextrins (CD) has been suggested as a solution. In this work, the host–guest inclusion complex between the ß-CD and EST has been prepared using four different methods. The obtained samples have been deeply characterized using ¹³C CP MAS solid state NMR, PXRD, FT-IR, TGA, DSC, and SEM. Using SCXRD, the crystal structure of the complex has been determined, being to the best of our knowledge the first solved crystal structure of an estrogen/CD complex. The periodic DFT calculations of NMR properties using GIPAW were found to be particularly helpful in the analysis of disorder in the solid state and interpretation of experimental NMR results. This work highlights the importance of a combined ssNMR/SCXRD approach to studying the structure of the inclusion complexes formed by cyclodextrins. Full article

(This article belongs to the Special Issue Cyclodextrin Chemistry and Toxicology II)

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Open AccessArticle

Characterization of Complexes between Imidacloprid and β-Cyclodextrin: Evaluation of the Toxic Activity in Algae and Rotifers

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Molecules 2023, 28(7), 3049; https://doi.org/10.3390/molecules28073049 - 29 Mar 2023

Viewed by 509

Abstract

The development of new formulations can be driven by the knowledge of host–guest complexes using cyclodextrins which have the ability to include guest molecules within their hydrophobic cavities, improving the physicochemical properties of the guest. To rationally explore new pesticide formulations, the effects [...] Read more.

The development of new formulations can be driven by the knowledge of host–guest complexes using cyclodextrins which have the ability to include guest molecules within their hydrophobic cavities, improving the physicochemical properties of the guest. To rationally explore new pesticide formulations, the effects of cyclodextrins on the properties of such guest molecules need to be explored. Imidacloprid is a neonicotinoid systemic insecticide used worldwide. In this study, the inclusion complexes of Imidacloprid (IMI) with β-cyclodextrin (β-CD) were prepared in the solid state by co-precipitation and the physical mixing method, with a stoichiometry of 1:1 and 1:2 molar ratios. The obtained products, Imidacloprid:β-cyclodextrin inclusion complex (IMI:β-CD), were characterized in the solid state by Fourier transform-infrared (FT-IR) spectroscopy and X-ray powder diffractometry (XRD). In solution, the 1:1 stoichiometry for the inclusion complexes was established by the Job plot method, and the binding constant of IMI:β-CD was determined by UV–vis titration. The toxicity was determined in producers and primary consumers of the freshwater trophic chain, the green alga Raphidocelis subcapitata and the rotifer Brachionus calyciflorus, respectively. The results indicated that Imidacloprid forms inclusion complexes with CDs showing improved physicochemical properties compared to free Imidacloprid. The formation of the inclusion complex reduced the chronic toxicity in rotifers when IMI concentrations were close to those of environmental concern (tenths/hundredths of micromoles/L). Therefore, CD inclusion complexes could provide important advantages to be considered for the future industrial production of new formulations. Full article

(This article belongs to the Special Issue Cyclodextrin Chemistry and Toxicology II)

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Open AccessArticle

Inclusions of Pesticides by β-Cyclodextrin in Solution and Solid State: Chlorpropham, Monuron, and Propanil

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Molecules 2023, 28(3), 1331; https://doi.org/10.3390/molecules28031331 - 30 Jan 2023

Cited by 1 | Viewed by 530

Abstract

Persistence and degradation are important factors in determining the safe use of such synthetic products, and numerous studies have been addressed to develop pesticide remediation methods aimed at ameliorating these features. In this frame, the use of different cyclodextrins (CDs) molecules has attracted [...] Read more.

Persistence and degradation are important factors in determining the safe use of such synthetic products, and numerous studies have been addressed to develop pesticide remediation methods aimed at ameliorating these features. In this frame, the use of different cyclodextrins (CDs) molecules has attracted considerable attention due to their well-known non-toxic nature, limited environmental impact, and capability to reduce the environmental and health risks of pesticides. CDs appear to be a valuable tool for the elimination of pesticides from polluted areas as well as for better pesticide formulations that positively influence their hydrolysis or degradation. The present work investigates the interaction between β-cyclodextrins and three commonly used pesticides (i.e., chlorpropham, monuron, and propanil) both in solution and in the solid state by means of UV-Vis, FT-IR, and X-ray powder diffractometry. We show that such interactions result in all three cases in the formation of inclusion complexes with a 1:1 stoichiometry and binding constants (K_b) of 369.9 M⁻¹ for chlorpropham, 292.3 M⁻¹ for monuron, and 298.3 M⁻¹ for propanil. We also report the energy-minimized structures in silico for each complex. Our data expand and complement the available literature data in indicating CDs as a low-cost and very effective tool capable of modulating the properties that determine the environmental fate of pesticides. Full article

(This article belongs to the Special Issue Cyclodextrin Chemistry and Toxicology II)

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Open AccessArticle

Chiral Separations of Pyrethroic Acids Using Cyclodextrin Selectors

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Zoltán Juvancz

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Rita Bodáné-Kendrovics

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Zita Laczkó

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Róbert Iványi

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Erzsébet Varga

Molecules 2022, 27(24), 8718; https://doi.org/10.3390/molecules27248718 - 09 Dec 2022

Viewed by 630

Abstract

Pyrethroid insecticides are broadly used. They have low toxicity for warm-blooded living creatures, but high toxicity for both insects and fish. Therefore, it is important to reduce the environmental impact of pyrethroids. Pyrethroic acids are chiral compounds. An effective way to decrease pollution [...] Read more.

Pyrethroid insecticides are broadly used. They have low toxicity for warm-blooded living creatures, but high toxicity for both insects and fish. Therefore, it is important to reduce the environmental impact of pyrethroids. Pyrethroic acids are chiral compounds. An effective way to decrease pollution is to use enantio-pure insecticide products instead of their racemic mixtures. Enantiomer-pure products require enantiomer selective synthesis and analysis. The chiral selective analysis of pyrethroic acids (an intermediate of pyrethroids) is also important in terms of process control and from the point of view of their degradation metabolism in the environment. This study used various enantiomeric selective chromatographic methods for the separation of different pyrethroic acids, including gas chromatography, supercritical fluid chromatography and capillary electrophoresis. Systematic experiments were conducted to find the optimum conditions for their chiral separation. The employed enantio-selective agents were cyclodextrin derivatives with different ring sizes and substitution patterns. The β-cyclodextrin proved to be excellent for the chiral separation of these acids. The different chiral recognition mechanisms were established using different ring-sized cyclodextrins. The results of these systematic studies demonstrated the correlations of the chiral selectivity features of selectors and the structures of analytes. Full article

(This article belongs to the Special Issue Cyclodextrin Chemistry and Toxicology II)

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Open AccessArticle

Morin-VitaminE-β-CyclodextrinInclusionComplexLoadedChitosanNanoparticles (M-Vit.E-CD-CSNPs) Ameliorate Arsenic-Induced Hepatotoxicityina Murine Model

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Sanchaita Mondal

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Sujata Das

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Pradip Kumar Mahapatra

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Krishna Das Saha

Molecules 2022, 27(18), 5819; https://doi.org/10.3390/molecules27185819 - 08 Sep 2022

Viewed by 836

Abstract

The special features of cyclodextrins (CDs), hydrophilic outer surfaces and hydrophobic inner surfaces, allow for development of inclusion complexes. The two bioactive strong antioxidant hepatoprotective compounds, Morin and vitamin E, are water insoluble. The present study aimed to prepare Morin-vitamin E-β-cyclodextrin inclusion complex [...] Read more.

The special features of cyclodextrins (CDs), hydrophilic outer surfaces and hydrophobic inner surfaces, allow for development of inclusion complexes. The two bioactive strong antioxidant hepatoprotective compounds, Morin and vitamin E, are water insoluble. The present study aimed to prepare Morin-vitamin E-β-cyclodextrin inclusion complex loaded chitosan nanoparticles (M-Vit.E-CD-CS NPs) and to examine their hepatoprotective efficacy against arsenic-induced toxicity in a murine model. The NPs were characterized by FTIR, DLS, NMR, DSC, XRD, AFM, and a TEM study. The NPs were spherical in shape, 178 ± 1.5 nm in size with a polydispersity index (PDI) value of 0.18 and a zeta potential value of −22.4 ± 0.31 mV, with >50% encapsulation and drug loading efficacy. Mice were exposed to arsenic via drinking water, followed by treatment without or with the NPs on every alternate day up to 30 days by oral gavaging. Administration of NPs inhibited the arsenic-induced elevation of liver function markers, inflammatory and proapoptotic factors, reactive oxygen species (ROS) production, alteration in the level of blood parameters and antioxidant factors, and liver damage, which was measured by different biochemical assays, ELISA, Western blot, and histological study. Organ distribution of nanoparticles was measured by HPLC. M-Vit.E-CD-CS NPs showing potent hepatoprotective activity may be therapeutically beneficial. Full article

(This article belongs to the Special Issue Cyclodextrin Chemistry and Toxicology II)

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Open AccessArticle

Preparation and Characterization of Disulfiram and Beta Cyclodextrin Inclusion Complexes for Potential Application in the Treatment of SARS-CoV-2 via Nebulization

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Molecules 2022, 27(17), 5600; https://doi.org/10.3390/molecules27175600 - 31 Aug 2022

Cited by 3 | Viewed by 1358

Abstract

Disulfiram (DS), known as an anti-alcoholism drug, has shown a potent antiviral activity. Still, the potential clinical application of DS is limited by its low water solubility and rapid metabolism. Cyclodextrins (CDs) have been widely used to improve the solubility of drugs in [...] Read more.

Disulfiram (DS), known as an anti-alcoholism drug, has shown a potent antiviral activity. Still, the potential clinical application of DS is limited by its low water solubility and rapid metabolism. Cyclodextrins (CDs) have been widely used to improve the solubility of drugs in water. In this study, five concentrations of hydroxypropyl β-cyclodextrin (HP) and sulfobutyl ether β-cyclodextrin (SBE) were used to form inclusion complexes of DS for enhanced solubility. Solutions were freeze-dried, and the interaction between DS and CD was characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). In addition, the nebulization properties of the DS–CD solutions were studied. The aqueous solubility of DS increased significantly when loaded to either of both CDs. The phase solubility of both complexes was a linear function of the CD concentration (A_L type). Furthermore, physicochemical characterization studies showed a potent inclusion of the drug in the CD–DS complexes. Aerosolization studies demonstrated that these formulations are suitable for inhalation. Overall, the CD inclusion complexes have great potential for the enhancement of DS solubility. However, further studies are needed to assess the efficacy of DS–CD inclusion complexes against SARS-CoV-2 via nebulization. Full article

(This article belongs to the Special Issue Cyclodextrin Chemistry and Toxicology II)

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Open AccessArticle

N,N-Diethyl-3-toluamide Formulation Based on Ethanol Containing 0.1% 2-Hydroxypropyl-β-cyclodextrin Attenuates the Drug’s Skin Penetration and Prolongs the Repellent Effect without Stickiness

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Molecules 2022, 27(10), 3174; https://doi.org/10.3390/molecules27103174 - 16 May 2022

Cited by 1 | Viewed by 990

Abstract

N,N-diethyl-3-toluamide (DEET) is one of the most widely used insect repellents in the world. It was reported that a solution containing 6–30% cyclodextrin (CD) as a solvent instead of ethanol (EtOH) provided an enhancement of the repellent action time duration [...] Read more.

N,N-diethyl-3-toluamide (DEET) is one of the most widely used insect repellents in the world. It was reported that a solution containing 6–30% cyclodextrin (CD) as a solvent instead of ethanol (EtOH) provided an enhancement of the repellent action time duration of the DEET formulation, although the high-dose CD caused stickiness. In order to overcome this shortcoming, we attempted to prepare a 10% DEET formulation using EtOH containing low-dose CDs (β-CD, 2-hydroxypropyl-β-CD (HPβCD), methyl-β-CD, and sulfobutylether-β-CD) as solvents (DEET/EtOH/CD formulations). We determined the CD concentration to be 0.1% in the DEET/EtOH/CD formulations, since the stickiness of 0.1% CDs was not felt (approximately 8 × 10⁻³ N). The DEET residue on the skin superficial layers was prolonged, and the drug penetration into the skin tissue was decreased by the addition of 0.1% CD. In particular, the retention time and attenuated penetration of DEET on the rat skin treated with the DEET/EtOH/HPβCD formulation was significantly higher in comparison with that of the DEET/EtOH formulation without CD. Moreover, the repellent effect of DEET was more sustained by the addition of 0.1% HPβCD in the study using Aedes albopictus. In conclusion, we found that the DEET/EtOH/HPβCD formulations reduced the skin penetration of DEET and prolonged the repellent action without stickiness. Full article

(This article belongs to the Special Issue Cyclodextrin Chemistry and Toxicology II)

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Open AccessArticle

Exploring In Vitro Biological Cellular Responses of Pegylated β-Cyclodextrins

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Juliana Rincón-López

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Miguelina Martínez-Aguilera

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Patricia Guadarrama

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Karla Juarez-Moreno

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Yareli Rojas-Aguirre

Molecules 2022, 27(9), 3026; https://doi.org/10.3390/molecules27093026 - 08 May 2022

Viewed by 1575

Abstract

βCDPEG5 and βCDPEG2 are two derivatives comprising seven PEG linear chains of 5 and 2 kDa, respectively, conjugated to βCD. As βCDPEGs display different physicochemical properties than their precursors, they could also trigger distinct cellular responses. To investigate the biological behavior of βCDPEGs [...] Read more.

βCDPEG5 and βCDPEG2 are two derivatives comprising seven PEG linear chains of 5 and 2 kDa, respectively, conjugated to βCD. As βCDPEGs display different physicochemical properties than their precursors, they could also trigger distinct cellular responses. To investigate the biological behavior of βCDPEGs in comparison to their parent compounds, we performed broad toxicological assays on RAW 264.7 macrophages, MC3T3-E1 osteoblasts, and MDCK cells. By analyzing ROS and NO₂⁻ overproduction in macrophages, we found that βCDPEGs induced a moderate stress response without affecting cell viability. Although MC3T3-E1 osteoblasts were more sensitive than MDCK cells to βCDPEGs and the parent compounds, a similar pattern was observed: the effect of βCDPEG5 on cell viability and cell cycle progression was larger than that of βCDPEG2; PEG2 affected cell viability and cell cycle more than βCDPEG2; cell post-treatment recovery was favorable in all cases, and the compounds had similar behaviors regarding ROS generation. The effect on MDCK cell migration followed a similar pattern. In contrast, for osteoblasts, the interference of βCDPEG5 with cell migration was smaller than that of βCDPEG2; likewise, the effect of PEG2 was shorter than its conjugate. Overall, the covalent conjugation of βCD and PEGs, particularly to yield βCDPEG2, improved the biocompatibility profile, evidencing that a favorable biological response can be tuned through a thoughtful combination of materials. Moreover, this is the first time that an in vitro evaluation of βCD and PEG has been presented for MC3T3-E1 and MDCK cells, thus providing valuable knowledge for designing biocompatible nanomaterials constructed from βCD and PEGs. Full article

(This article belongs to the Special Issue Cyclodextrin Chemistry and Toxicology II)

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Open AccessArticle

β-Cyclodextrin as the Key Issue in Production of Acceptable Low-Cholesterol Dairy Products

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Lukáš Kolarič

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Petra Kántorová

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Peter Šimko

Molecules 2022, 27(9), 2919; https://doi.org/10.3390/molecules27092919 - 03 May 2022

Cited by 1 | Viewed by 1199

Abstract

The application of cyclodextrins in food technology is extensive due to their unique ability to form complexes with many bioactive substances. Consumption of dairy products is associated with an increased risk of cardiovascular diseases (CVD) due to its high content of saturated fatty [...] Read more.

The application of cyclodextrins in food technology is extensive due to their unique ability to form complexes with many bioactive substances. Consumption of dairy products is associated with an increased risk of cardiovascular diseases (CVD) due to its high content of saturated fatty acids and cholesterol, so the production of low-cholesterol content products would be one of the critical steps in CVD prevention with regards to lowered total daily cholesterol intake. To maintain consumer acceptance, organoleptic profiles of such products should be, in the optimal case, the same with comparison to original ones. So, this study deals with the development of set low cholesterol foods (milk, cream, butter, soft cheese, cottage cheese) by β-cyclodextrin treatment and the characterization of their organoleptic profiles such as color and textural characteristics. During the experiments, high effectivity of cholesterol removal was reached as follows: milk–97.3%, cream–95.6%, butter–95.6%, cottage cheese–97.9%, soft cheese–97.7%, while color differences varied from 0.25 to 1.13 and textural characteristics were not influenced by cholesterol removal as well. So, it can be concluded that the proposed procedure is enabled to be substantial for the production of a new assortment of low-cholesterol dairy products with considerable health benefits toward the incidence of CVD. Full article

(This article belongs to the Special Issue Cyclodextrin Chemistry and Toxicology II)

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Open AccessArticle

Manufacturing and Assessing the New Orally Disintegrating Tablets, Containing Nimodipine-hydroxypropyl-β-cyclodextrin and Nimodipine-methyl-β-cyclodextrin Inclusion Complexes

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Marian Novac

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Adina Magdalena Musuc

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Molecules 2022, 27(6), 2012; https://doi.org/10.3390/molecules27062012 - 21 Mar 2022

Cited by 2 | Viewed by 1371

Abstract

The aim of the present study was to manufacture new orally disintegrating tablets containing nimodipine–hydroxypropyl-β-cyclodextrin and nimodipine–methyl-β-cyclodextrin inclusion complexes. For obtaining a better quality of the manufactured tablets, three methods of the preparation of inclusion complexes, in a 1:1 molar ratio, were used [...] Read more.

The aim of the present study was to manufacture new orally disintegrating tablets containing nimodipine–hydroxypropyl-β-cyclodextrin and nimodipine–methyl-β-cyclodextrin inclusion complexes. For obtaining a better quality of the manufactured tablets, three methods of the preparation of inclusion complexes, in a 1:1 molar ratio, were used comparatively; namely, a solid-state kneading method and two liquid state coprecipitation and lyophilization techniques. The physical and chemical properties of the obtained inclusion complexes, as well as their physical mixtures, were investigated using Fourier transformed infrared spectroscopy, scanning electron microscopy, X-ray diffraction analyses, and differential scanning calorimetry. The results showed that the lyophilization method can be successfully used for a better complexation. Finally, the formulation and precompression studies for tablets for oral dispersion, containing Nim–HP-β-CD and Nim–Me-β-CD inclusion complexes, were successfully assessed. Full article

(This article belongs to the Special Issue Cyclodextrin Chemistry and Toxicology II)

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Open AccessArticle

Synthesis of Mono-Amino Substituted γ-CD: Host–Guest Complexation and In Vitro Cytotoxicity Investigation

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Molecules 2022, 27(5), 1683; https://doi.org/10.3390/molecules27051683 - 04 Mar 2022

Viewed by 1527

Abstract

Cyclodextrins (CDs) are cyclic oligosaccharides which can trap hydrophobic molecules and improve their chemical, physical, and biological properties. γ-CD showed the highest aqueous solubility with the largest cavity diameter among other CD types. The current study describes a direct and easy method for [...] Read more.

Cyclodextrins (CDs) are cyclic oligosaccharides which can trap hydrophobic molecules and improve their chemical, physical, and biological properties. γ-CD showed the highest aqueous solubility with the largest cavity diameter among other CD types. The current study describes a direct and easy method for nucleophilic mono-aminos to be substituted with γ-CD and tested for their ability to host the guest curcumin (CUR) as a hydrophobic drug model. The mass spectrometry and NMR analyses showed the successful synthesis of three amino-modified γ-CDs: mono-6-amino-6-deoxy-cyclodextrine (γ-CD-NH₂), mono-6-deoxy-6-ethanolamine-γ-cyclodextrine (γ-CD-NHCH₂CH₂OH), and mono-6-deoxy-6-aminoethylamino)-γ-cyclodextrin (γ-CD-NHCH₂CH₂NH₂). These three amino-modified γ-CDs were proven to be able to host CUR as native γ-CDs with formation constants equal to 6.70 ± 1.02, 5.85 ± 0.80, and 8.98 ± 0.90 mM⁻¹, respectively. Moreover, these amino-modified γ-CDs showed no significant toxicity against human dermal fibroblast cells. In conclusion, the current work describes a mono-substitution of amino-modified γ-CDs that can still host guests and showed low toxicity in human dermal fibroblasts cells. Therefore, the amino-modified γ-CDs can be used as a carrier host and be conjugated with a wide range of molecules for different biomedical applications, especially for active loading methods. Full article

(This article belongs to the Special Issue Cyclodextrin Chemistry and Toxicology II)

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Open AccessArticle

Cellular Effects of Cyclodextrins: Studies on HeLa Cells

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Katalin Szászné Réti-Nagy

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Gábor Vasvári

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Ádám Haimhoffer

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Ferenc Fenyvesi

Molecules 2022, 27(5), 1589; https://doi.org/10.3390/molecules27051589 - 28 Feb 2022

Cited by 1 | Viewed by 1709

Abstract

Cyclodextrins are high molecular weight, hydrophilic, cyclic, non-reducing oligosaccharides, applied as excipients for the improvement of the solubility and permeability of insoluble active pharmaceutical ingredients. On the other hand, beta-cyclodextrins are used as cholesterol sequestering agents in life sciences. Recently, we demonstrated the [...] Read more.

Cyclodextrins are high molecular weight, hydrophilic, cyclic, non-reducing oligosaccharides, applied as excipients for the improvement of the solubility and permeability of insoluble active pharmaceutical ingredients. On the other hand, beta-cyclodextrins are used as cholesterol sequestering agents in life sciences. Recently, we demonstrated the cellular internalization and intracellular effects of cyclodextrins on Caco-2 cells. In this study, we aimed to further investigate the endocytosis of (2-hydroxylpropyl)-beta-(HPBCD) and random methylated-beta-cyclodextrin (RAMEB) to test their cytotoxicity, NF-kappa B pathway induction, autophagy, and lysosome formation on HeLa cells. These derivatives were able to enter the cells; however, major differences were revealed in the inhibition of their endocytosis compared to Caco-2 cells. NF-kappa B p65 translocation was not detected in the cell nuclei after HPBCD or RAMEB pre-treatment and cyclodextrin treatment did not enhance the formation of autophagosomes. These cyclodextrin derivates were partially localized in lysosomes after internalization. Full article

(This article belongs to the Special Issue Cyclodextrin Chemistry and Toxicology II)

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Open AccessArticle

Novel β-Cyclodextrin and Catnip Essential Oil Inclusion Complex and Its Tick Repellent Properties

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Jennifer Hogenbom

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Mouaz Istanbouli

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Nicoletta Faraone

Molecules 2021, 26(23), 7391; https://doi.org/10.3390/molecules26237391 - 06 Dec 2021

Cited by 6 | Viewed by 2193

Abstract

Cyclodextrin inclusion complexes have been successfully used to encapsulate essential oils, improving their physicochemical properties and pharmacological effects. Besides being well-known for its effects on cats and other felines, catnip (Nepeta cataria) essential oil demonstrates repellency against blood-feeding pests such as [...] Read more.

Cyclodextrin inclusion complexes have been successfully used to encapsulate essential oils, improving their physicochemical properties and pharmacological effects. Besides being well-known for its effects on cats and other felines, catnip (Nepeta cataria) essential oil demonstrates repellency against blood-feeding pests such as mosquitoes. This study evaluates the tick repellency of catnip oil alone and encapsulated in β-cyclodextrin, prepared using the co-precipitation method at a 1:1 molar ratio. The physicochemical properties of this inclusion complex were characterized using GC-FID for encapsulation efficiency and yield and SPME/GC-MS for volatile emission. Qualitative assessment of complex formation was done by UV-Vis, FT-IR, ¹H NMR, and SEM analyses. Catnip oil at 5% (v/v) demonstrated significant tick repellency over time, being comparable to DEET as used in commercial products. The prepared [catnip: β-CD] inclusion complex exerted significant tick repellency at lower concentration of the essential oil (equivalent of 1% v/v). The inclusion complex showed that the release of the active ingredient was consistent after 6 h, which could improve the effective repellent duration. These results demonstrated the effective tick repellent activity of catnip essential oil and the successful synthesis of the inclusion complex, suggesting that β-CDs are promising carriers to improve catnip oil properties and to expand its use in repellent formulations for tick management. Full article

(This article belongs to the Special Issue Cyclodextrin Chemistry and Toxicology II)

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Open AccessReview

Comparison of the Conventional and Mechanochemical Syntheses of Cyclodextrin Derivatives

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Molecules 2023, 28(2), 467; https://doi.org/10.3390/molecules28020467 - 04 Jan 2023

Cited by 1 | Viewed by 1096

Abstract

Many scientists are working hard to find green alternatives to classical synthetic methods. Today, state-of-the-art ultrasonic and grinding techniques already drive the production of organic compounds on an industrial scale. The physicochemical and chemical behavior of cyclodextrins often differs from the typical properties [...] Read more.

Many scientists are working hard to find green alternatives to classical synthetic methods. Today, state-of-the-art ultrasonic and grinding techniques already drive the production of organic compounds on an industrial scale. The physicochemical and chemical behavior of cyclodextrins often differs from the typical properties of classic organic compounds and carbohydrates. The usually poor solubility and complexing properties of cyclodextrins can require special techniques. By eliminating or reducing the amount of solvent needed, green alternatives can reform classical synthetic methods, making them attractive for environmentally friendly production and the circular economy. The lack of energy-intensive synthetic and purification steps could transform currently inefficient processes into feasible methods. Mechanochemical reaction mechanisms are generally different from normal solution-chemistry mechanisms. The absence of a solvent and the presence of very high local temperatures for microseconds facilitate the synthesis of cyclodextrin derivatives that are impossible or difficult to produce under classical solution-chemistry conditions. Although mechanochemistry does not provide a general solution to all problems, several good examples show that this new technology can open up efficient synthetic pathways. Full article

(This article belongs to the Special Issue Cyclodextrin Chemistry and Toxicology II)

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Open AccessReview

Current Status of Quantum Chemical Studies of Cyclodextrin Host–Guest Complexes

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Anna Helena Mazurek

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Łukasz Szeleszczuk

Molecules 2022, 27(12), 3874; https://doi.org/10.3390/molecules27123874 - 16 Jun 2022

Cited by 7 | Viewed by 1648

Abstract

This article aims to review the application of various quantum chemical methods (semi-empirical, density functional theory (DFT), second order Møller–Plesset perturbation theory (MP2)) in the studies of cyclodextrin host–guest complexes. The details of applied approaches such as functionals, basis sets, dispersion corrections or [...] Read more.

This article aims to review the application of various quantum chemical methods (semi-empirical, density functional theory (DFT), second order Møller–Plesset perturbation theory (MP2)) in the studies of cyclodextrin host–guest complexes. The details of applied approaches such as functionals, basis sets, dispersion corrections or solvent treatment methods are analyzed, pointing to the best possible options for such theoretical studies. Apart from reviewing the ways that the computations are usually performed, the reasons for such studies are presented and discussed. The successful applications of theoretical calculations are not limited to the determination of stable conformations but also include the prediction of thermodynamic properties as well as UV–Vis, IR, and NMR spectra. It has been shown that quantum chemical calculations, when applied to the studies of CD complexes, can provide results unobtainable by any other methods, both experimental and computational. Full article

(This article belongs to the Special Issue Cyclodextrin Chemistry and Toxicology II)

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