Interactions between cyclodextrins and cellular components: Towards greener medical applications?

Rationally designed β-cyclodextrin-crosslinked polyacrylamide hydrogels for cell spheroid formation and 3D tumor model construction

In vitro tumor models are essential for understanding tumor behavior and evaluating tumor biological properties. Hydrogels that can mimic the tumor extracellular matrix have become popular for creating 3D in vitro tumor models. However, designing biocompatible hydrogels with appropriate chemical and physical properties for constructing tumor models is still a challenge. In this study, we synthesized a series of β-cyclodextrin (β-CD)-crosslinked polyacrylamide hydrogels with different β-CD densities and mechanical properties and evaluated their potential for use in 3D in vitro tumor model construction, including cell capture and spheroid formation. By utilizing a combination of β-CD-methacrylate (CD-MA) and a small amount of N,N'-methylene bisacrylamide (BIS) as hydrogel crosslinkers and optimizing the CD-MA/BIS ratio, the hydrogels performed excellently for tumor cell 3D culture and spheroid formation. Notably, when we co-cultured L929 fibroblasts with HeLa tumor cells on the hydrogel surface, co-cultured spheroids were formed, showing that the hydrogel can mimic the complexity of the tumor extracellular matrix. This comprehensive investigation of the relationship between hydrogel mechanical properties and biocompatibility provides important insights for hydrogel-based in vitro tumor modeling and advances our understanding of the mechanisms underlying tumor growth and progression.

The Impact of Cyclodextrins on the Physiology of Candida boidinii: Exploring New Opportunities in the Cyclodextrin Application

Cyclodextrins, commonly used as excipients in antifungal formulations to improve the physicochemical properties and availability of the host molecules, have not been systematically studied for their effects and bioactivity without a complex active substance. This paper evaluates the effects of various cyclodextrins on the physiology of the test organism Candida boidinii. The research examines their impact on yeast growth, viability, biofilm formation and morphological changes. Native ACD, BCD, randomly methylated α- and β-CD and quaternary ammonium α-CD and β-CD were investigated in the 0.5-12.5 mM concentration range in both static and dynamic systems. The study revealed that certain cyclodextrins exhibited notable antifungal effects (up to ~69%) in dynamic systems; however, the biofilm formation was enhanced in static systems. The magnitude of these effects was influenced by several variables, including the size of the internal cavity, the concentration and structure of the cyclodextrins, and the contact time. Furthermore, the study found that CDs exhibited distinct effects in both static and dynamic systems, potentially related to their tendency to form aggregates. The findings suggest that cyclodextrins may have the potential to act as antifungal agents or growth promoters, depending on their structure and surrounding environments.

Chitosan and Cyclodextrins-Versatile Materials Used to Create Drug Delivery Systems for Gastrointestinal Cancers

Gastrointestinal cancers are characterized by a frequent incidence, a high number of associated deaths, and a tremendous burden on the medical system and patients worldwide. As conventional chemotherapeutic drugs face numerous limitations, researchers started to investigate better alternatives for extending drug efficacy and limiting adverse effects. A remarkably increasing interest has been addressed to chitosan and cyclodextrins, two highly versatile natural carbohydrate materials endowed with unique physicochemical properties. In this respect, numerous studies reported on fabricating various chitosan and cyclodextrin-based formulations that enabled prolonged circulation times, improved cellular internalization of carried drugs, preferential uptake by the targeted cells, reduced side effects, enhanced apoptosis rates, and increased tumor suppression rates. Therefore, this paper aims to briefly present the advantageous properties of these oligo- and polysaccharides for designing drug delivery systems, further focusing the discussion on nanocarrier systems based on chitosan/cyclodextrins for treating different gastrointestinal cancers. Specifically, there are reviewed studies describing promising solutions for colorectal, liver, gastric, pancreatic, and other types of cancers of the digestive system towards creating an updated framework of what concerns anticancer chitosan/cyclodextrin-based drug delivery systems.

Change in the Kinetic Regime of Aggregation of Yeast Alcohol Dehydrogenase in the Presence of 2-Hydroxypropyl-β-cyclodextrin

Chemical chaperones are low-molecular-weight compounds that suppress protein aggregation. They can influence different stages of the aggregation process-the stage of protein denaturation, the nucleation stage and the stage of aggregate growth-and this may lead to a change in the aggregation kinetic regime. Here, the possibility of changing the kinetic regime in the presence of a chemical chaperone 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD) was investigated for a test system based on the thermally induced aggregation of yeast alcohol dehydrogenase (yADH) at 56 °C. According to differential scanning calorimetry data, 2-HP-β-CD did not affect the stage of the protein molecule unfolding. Dynamic light scattering data indicated changes in the aggregation kinetics of yADH during the nucleation and aggregate growth stages in the presence of the chaperone. The analysis of kinetic curves showed that the order of aggregation with respect to protein (nc), calculated for the stage of aggregate growth, changed from nc = 1 to nc = 2 with the addition of 100 mM 2-HP-β-CD. The mechanism of 2-HP-β-CD action on the yADH thermal aggregation leading to a change in its kinetic regime of aggregation is discussed.

Active and Intelligent Packaging: A Review of the Possible Application of Cyclodextrins in Food Storage and Safety Indicators

Natural cyclodextrins (CDs) can be formed by 6, 7, or 8 glucose molecules (α-, β-, and γ-, respectively) linked in a ring, creating a cone shape. Its interior has an affinity for hydrophobic molecules, while the exterior is hydrophilic and can interact with water molecules. This feature has been used to develop active packaging applied to food, interacting with the product or its environment to improve one or more aspects of its quality or safety. It also provides monitoring information when food is optimal for consumption, as intelligent packaging is essential for the consumer and the merchant. Therefore, this review will focus on discerning which packaging is most appropriate for each situation, solubility and toxicological considerations, characterization techniques, effect on the guest properties, and other aspects related to forming the inclusion complex with bioactive molecules applied to packaging.

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.

Cyclodextrin-Based Nanoparticles for Delivery of Antisense Oligonucleotides Targeting Huntingtin

Huntington's disease (HD) is a progressive inherited neurodegenerative disease caused by a CAG repeat expansion in the huntingtin gene, which is translated into the pathologic mutant huntingtin (mHTT) protein. Despite the great potential of HTT lowering strategies and the numerous antisense oligonucleotides (ASOs) in pre- and clinical trials, sustained silencing of mHTT has not been achieved. As a strategy to improve ASO delivery, cyclodextrin-based nanoparticles (CDs) offer a promising approach. Here, three CDs with distinct chemical structures were designed and their efficacies were compared as potential platforms for the delivery of ASO targeting HTT. Results using striatal neurons and HD patient-derived fibroblasts indicate that modified γ-CDs exhibited the best uptake efficiency and successfully downregulated mHTT at protein and allele levels. The incorporation of the brain-targeting peptide RVG into the modified γ-CDs showed greater downregulation of mHTT protein and HD-causing allele SNP1 than untargeted ones in an in vitro blood-brain barrier model. Although the ASO sequence was designed as a nonallele-specific therapeutic approach, our strategy gives an additional benefit of some mHTT selectivity. Overall, this study demonstrated the CD platform's feasibility for delivering ASO-based therapeutics for HD treatment.

A New Synergistic Strategy for Virus and Bacteria Eradication: Towards Universal Disinfectants

In response to the COVID-19 and monkeypox outbreaks, we present the development of a universal disinfectant to avoid the spread of infectious viral diseases through contact with contaminated surfaces. The sanitizer, based on didecyldimethylammonium chloride (DDAC), N,N-bis(3-aminopropyl)dodecylamine (APDA) and γ-cyclodextrin (γ-CD), shows synergistic effects against non-enveloped viruses (poliovirus type 1 and murine norovirus) according to the EN 14476 standard (≥99.99% reduction of virus titer). When a disinfectant product is effective against them, it can be considered that it will be effective against all types of viruses, including enveloped viruses. Consequently, "general virucidal activity" can be claimed. Moreover, we have extended this synergistic action to bacteria (P. aeruginosa, EN 13727). Based on physicochemical investigations, we have proposed two independent mechanisms of action against bacteria and non-enveloped viruses, operating at sub- and super-micellar concentrations, respectively. This synergistic mixture could then be highly helpful as a universal disinfectant to avoid the spread of infectious viral or bacterial diseases in community settings, including COVID-19 and monkeypox (caused by enveloped viruses).

An Updated Overview of Cyclodextrin-Based Drug Delivery Systems for Cancer Therapy

Encompassing a group of complex and heterogeneous diseases, cancer continues to be a challenge for patients and healthcare systems worldwide. Thus, it is of vital importance to develop advanced treatment strategies that could reduce the trends of cancer-associated morbidity and mortality rates. Scientists have focused on creating performant delivery vehicles for anti-cancer agents. Among the possible materials, cyclodextrins (CDs) attracted increasing interest over the past few years, leading to the emergence of promising anti-tumor nanomedicines. Tackling their advantageous chemical structure, ease of modification, natural origin, biocompatibility, low immunogenicity, and commercial availability, researchers investigated CD-based therapeutical formulations against many types of cancer. In this respect, in this paper, we briefly present the properties of interest of CDs for designing performant nanocarriers, further reviewing some of the most recent potential applications of CD-based delivery systems in cancer management.

An Updated Overview of Cyclodextrin-Based Drug Delivery Systems for Cancer Therapy

Encompassing a group of complex and heterogeneous diseases, cancer continues to be a challenge for patients and healthcare systems worldwide. Thus, it is of vital importance to develop advanced treatment strategies that could reduce the trends of cancer-associated morbidity and mortality rates. Scientists have focused on creating performant delivery vehicles for anti-cancer agents. Among the possible materials, cyclodextrins (CDs) attracted increasing interest over the past few years, leading to the emergence of promising anti-tumor nanomedicines. Tackling their advantageous chemical structure, ease of modification, natural origin, biocompatibility, low immunogenicity, and commercial availability, researchers investigated CD-based therapeutical formulations against many types of cancer. In this respect, in this paper, we briefly present the properties of interest of CDs for designing performant nanocarriers, further reviewing some of the most recent potential applications of CD-based delivery systems in cancer management.

Deoxycholic acid induces proinflammatory cytokine production by model oesophageal cells via lipid rafts

The bile acid component of gastric refluxate has been implicated in inflammation of the oesophagus including conditions such as gastro-oesophageal reflux disease (GORD) and Barrett's Oesophagus (BO). Here we demonstrate that the hydrophobic bile acid, deoxycholic acid (DCA), stimulated the production of IL-6 and IL-8 mRNA and protein in Het-1A, a model of normal oesophageal cells. DCA-induced production of IL-6 and IL-8 was attenuated by pharmacologic inhibition of the Protein Kinase C (PKC), MAP kinase, tyrosine kinase pathways, by the cholesterol sequestering agent, methyl-beta-cyclodextrin (MCD) and by the hydrophilic bile acid, ursodeoxycholic acid (UDCA). The cholesterol-interacting agent, nystatin, which binds cholesterol without removing it from the membrane, synergized with DCA to induce IL-6 and IL-8. This was inhibited by the tyrosine kinase inhibitor genistein. DCA stimulated the phosphorylation of lipid raft component Src tyrosine kinase (Src). while knockdown of caveolin-1 expression using siRNA resulted in a decreased level of IL-8 production in response to DCA. Taken together, these results demonstrate that DCA stimulates IL-6 and IL-8 production in oesophageal cells via lipid raft-associated signaling. Inhibition of this process using cyclodextrins represents a novel therapeutic approach to the treatment of inflammatory diseases of the oesophagus including GORD and BO.

Cyclodextrins in the antiviral therapy

The main antiviral drug-cyclodextrin interactions, changes in physicochemical and physiological properties of the most commonly used virucides are summarized. The potential complexation of antiviral molecules against the SARS-Cov2 also pointed out the lack of detailed information in designing effective and general medicines against viral infections. The principal problem of the current molecules is the 3D structures of the currently active compounds. Improving the solubility or bioavailability of antiviral molecules is possible, however, there is no universal solution, and the complexation experiments dominantly use the already approved cyclodextrin derivatives. This review discusses the basic properties of the different cyclodextrin derivatives, their potential in antiviral formulations, and the prevention and treatment of viral infections. The biologically active new cyclodextrin derivatives are also discussed.

Investigation of Vitamin D2 and Vitamin D3 Hydroxylation by Kutzneria albida

The active vitamin D metabolites 25-OH-D and 1α,25-(OH)2 -D play an essential role in controlling several cellular processes in the human body and are potentially effective in the treatment of several diseases, such as autoimmune diseases, cardiovascular diseases and cancer. The microbial synthesis of vitamin D2 (VD2 ) and vitamin D3 (VD3 ) metabolites has emerged as a suitable alternative to established complex chemical syntheses. In this study, a novel strain, Kutzneria albida, with the ability to form 25-OH-D2 and 25-OH-D3 was identified. To further improve the conversion of the poorly soluble substrates, several solubilizers were tested. 100-fold higher product concentrations of 25-OH-D3 and tenfold higher concentrations of 25-OH-D2 after addition of 5 % (w/v) 2-hydroxypropyl β-cyclodextrin (2-HPβCD) were reached. Besides the single-hydroxylation products, the human double-hydroxylation products 1,25-(OH)2 -D2 and 1,25-(OH)2 -D3 and various other potential single- and double-hydroxylation products were detected. Thus, K. albida represents a promising strain for the biotechnological production of VD2 and VD3 metabolites.

Highly Active, Entirely Biobased Antimicrobial Pickering Emulsions

We present the development of surfactant-free, silica-free and fully biobased oil-in-water antimicrobial Pickering emulsions, based on the self-assembly of β-cyclodextrin and phytoantimicrobial oils (terpinen-4-ol or carvacrol). Undecylenic acid (UA), derived from castor oil, can be used as bio-based drug to treat fungal infection, but is less effective than petroleum-based drugs as azole derivatives. To maximize its antifungal potential, we have incorporated UA in fully biobased Pickering emulsions. These emulsions are effective against fungi, Gram-positive and Gram-negative bacteria. The carvacrol emulsion charged with UA is +390 % and +165 % more potent against methicillin-resistant S. aureus (MRSA), compared to UA and azole-based commercial formulations. Moreover, this emulsion is up to +480 % more efficient that UA ointment against C. albicans. Finally, remarkable eradication of E. coli and MRSA biofilms was obtained with this environmental-friendly emulsion.

Development of an LC-MS/MS method for simultaneous quantitative analysis of macromolecular pharmaceutical adjuvant 2-hydroxypropyl-β-cyclodextrin and active pharmaceutical ingredients butylphthalide in rat plasma

Hydroxypropyl-β-cyclodextrin, which possesses a high water solubility and low hemolycity, is widely used as a solubilizer and an excipient. It had also been reported that hydroxypropyl-β-cyclodextrin has the activity of regulating lipid homeostasis. In order to further understand the metabolism, the primary focus was to establish a quantitative method for hydroxypropyl-β-cyclodextrin. The analytes were extracted from plasma by protein precipitation with methanol and then carried out on a Waters CORTECS T3 column in the gradient elution of pure water and methanol. Finally, liquid chromatography-tandem mass spectrometry was applied in multiple reaction monitoring mode to complete the quantitative analysis of hydroxypropyl-β-cyclodextrin. This validated method had been successfully applied to investigate the interaction between hydroxypropyl-β-cyclodextrin and butylphthalide in vivo by optimizing the extraction reagent, simplifying the experimental procedure, and improving the sensitivity while considering the difference of drug chemical properties. Results showed that the inclusion of hydroxypropyl-β-cyclodextrin with butylphthalide significantly improved the pharmacokinetic behavior of free body hydroxypropyl-β-cyclodextrin and 3-n-butylphthalide in vivo. It had been implied that the metabolism of hydroxypropyl-β-cyclodextrin and the drug active ingredients could impact each other. It will help better application of hydroxypropyl-β-cyclodextrin and the developed method might lay the foundation for development of hydroxypropyl-β-cyclodextrin as a treatment drug for brain diseases.

Anti-platelet Drug-loaded Targeted Technologies for the Effective Treatment of Atherothrombosis

Atherothrombosis results from direct interaction between atherosclerotic plaque and arterial thrombosis and is the most common type of cardiovascular disease. As a long term progressive disease, atherosclerosis frequently results in an acute atherothrombotic event through plaque rupture and platelet-rich thrombus formation. The pathophysiology of atherothrombosis involves cholesterol accumulation endothelial dysfunction, dyslipidemia, immuno-inflammatory, and apoptotic aspects. Platelet activation and aggregation is the major cause for stroke because of its roles, including thrombus, contributing to atherosclerotic plaque, and sealing off the bleeding vessel. Platelet aggregates are associated with arterial blood pressure and cardiovascular ischemic events. Under normal physiological conditions, when a blood vessel is damaged, the task of platelets within the circulation is to arrest the blood loss. Antiplatelet inhibits platelet function, thereby decreasing thrombus formation with complementary modes of action to prevent atherothrombosis. In the present scientific scenario, researchers throughout the world are focusing on the development of novel drug delivery systems to enhance patient's compliance. Immediate responding pharmaceutical formulations become an emerging trend in the pharmaceutical industries with better patient compliance. The proposed review provides details related to the molecular pathogenesis of atherothrombosis and recent novel formulation approaches to treat atherothrombosis with particular emphasis on commercial formulation and upcoming technologies.

Cytotoxicity of β-Cyclodextrins in Retinal Explants for Intravitreal Drug Formulations

Cyclodextrins (CDs) have been widely used as pharmaceutical excipients for formulation purposes for different delivery systems. Recent studies have shown that CDs are able to form complexes with a variety of biomolecules, such as cholesterol. This has subsequently paved the way for the possibility of using CDs as drugs in certain retinal diseases, such as Stargardt disease and retinal artery occlusion, where CDs could absorb cholesterol lumps. However, studies on the retinal toxicity of CDs are limited. The purpose of this study was to examine the retinal toxicity of different beta-(β)CD derivatives and their localization within retinal tissues. To this end, we performed cytotoxicity studies with two different CDs—2-hydroxypropyl-βCD (HPβCD) and randomly methylated β-cyclodextrin (RMβCD)—using wild-type mouse retinal explants, the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and fluorescence microscopy. RMβCD was found to be more toxic to retinal explants when compared to HPβCD, which the retina can safely tolerate at levels as high as 10 mM. Additionally, studies conducted with fluorescent forms of the same CDs showed that both CDs can penetrate deep into the inner nuclear layer of the retina, with some uptake by Müller cells. These results suggest that HPβCD is a safer option than RMβCD for retinal drug delivery and may advance the use of CDs in the development of drugs designed for intravitreal administration.

Encapsulation of the Natural Product Tyrosol in Carbohydrate Nanosystems and Study of Their Binding with ctDNA

Tyrosol, a natural product present in olive oil and white wine, possesses a wide range of bioactivity. The aim of this study was to optimize the preparation of nanosystems encapsulating tyrosol in carbohydrate matrices and the investigation of their ability to bind with DNA. The first encapsulation matrix of choice was chitosan using the ionic gelation method. The second matrix was β-cyclodextrin (βCD) using the kneading method. Coating of the tyrosol-βCD ICs with chitosan resulted in a third nanosystem with very interesting properties. Optimal preparation parameters of each nanosystem were obtained through two three-factor, three-level Box-Behnken experimental designs and statistical analysis of the results. Thereafter, the nanoparticles were evaluated for their physical and thermal characteristics using several techniques (DLS, NMR, FT-IR, DSC, TGA). The study was completed with the investigation of the impact of the encapsulation on the ability of tyrosol to bind to calf thymus DNA. The results revealed that tyrosol and all the studied systems bind to the minor groove of ctDNA. Tyrosol interacts with ctDNA via hydrogen bond formation, as predicted via molecular modeling studies and corroborated by the experiments. The tyrosol-chitosan nanosystem does not show any binding to ctDNA whereas the βCD inclusion complex shows analogous interaction with that of free tyrosol.

Modulation of the Cholesterol-Dependent Activity of Macrophages IC-21 by CRAC Peptides with Substituted Motif-Forming Amino Acids

The activity of many membrane proteins, such as receptors, ionic channels, transporters, and enzymes, is cholesterol dependent; however, mechanisms of the cholesterol-dependent regulation of protein functions remain obscure. Recent studies suggest that membrane proteins can directly interact with cholesterol owing to the presence of the cholesterol-recognizing amino-acid consensus (CRAC) motifs. One of the ways to verify and further develop this notion is a design of CRAC-containing peptides and investigation of their effects on cholesterol-dependent cell functions. Previously we showed that a newly constructed peptide RTKLWEMLVELGNMDKAVKLWRKLKR (peptide P4) containing two CRAC motifs modulates cholesterol-dependent interactions of cultured macrophages IC-21 with 2-μm particles. In this work, in order to clarify the role of CRAC-forming amino acids, we employed the same experimental system to test the activity of peptides closely related to P4 but with modified CRAC motifs. We found that peptide STKLSEMLSELGNMDKASKLSRKLSR (Mut2) analogous to P4, except that all CRAC-forming amino acids (V, W, K/R) were substituted by serine, did not produce any effect in the concentration range 0.5-50 μM corresponding to the range of the P4 activity. Neither was effective peptide RTKLSEMLVELGNMDKAVKLSRKLKR (Mut3), in which only aromatic amino acids (W) of the CRAC motifs were substituted. Peptide STKLWEMLVELGNMDKAVKLWRKLSR (Mut4), in which only cationic amino acids (R/K) in the CRAC motifs were changed, produced almost the same effect as that of peptide P4 with a bell-shape dose-response curve. At low concentrations (1-4 μM) Mut4 notably increased the number of beads per cell, at higher concentrations this parameter diminished, and at 50 μM Mut4 produced a robust toxic effect. Finally, peptide EWGMAVLWERNRKLKKDLKVLKMLRT (Mut1) composed of the same amino acid residues as P4 but in a random order ("scramble") and possessing one CRAC motif, different from that in P4, produced a moderate stimulation at 4-10 μM but was not toxic at 50 μM. As in the case of peptide P4, the effects of Mut4 and Mut1 depended on the cholesterol content in the cell membrane: after the incubation of cells with cholesterol-extracting agent methyl-β-cyclodextrin stimulatory effects produced by Mut4 and Mut1 at low doses were suppressed. Our results indicate that CRAC motifs play an important role in the mechanisms of the peptide-induced modulations of cholesterol-dependent cell functions in the experimental system used and that of the three motif-forming amino acids, critical is the presence of the aromatic amino acid (W). Further research is required to comprehend the molecular mechanisms of interactions of CRAC-containing peptides with cell membrane components that lead to modulation of cell functions. We anticipate that CRAC-containing peptides may provide a basis for the development of new tools for directed regulation of the activity of target cholesterol-dependent membrane proteins and for the design of new antimicrobial and immunomodulating drugs in particular.

How to improve the chemical disinfection of contaminated surfaces by viruses, bacteria and fungus?

In response to the current pandemic situation, we present the development of an effective virucidal and biocidal solution to prevent from the spread of infectious diseases through contact with contaminated surfaces. The disinfectants, based on equimolar mixtures of didecyldimethylammonium chloride ([DiC10][Cl]), dodecyloctaglycol (C12E8), and cyclodextrin (CD), show synergistic effects against enveloped viruses (RSV, HSV-1, VACV) and fungi (C. albicans), and additive responses against bacteria (P. aeruginosa). These synergistic mixtures could then be highly helpful for prevention of respiratory illnesses, since a boosted activity allows: (i) a faster eradication of pathogens, (ii) a shorter contact time, and (iii) a complete and broad-spectrum eradication to avoid spread of resistant strains (including bacteria and fungi).

Improving silymarin oral bioavailability using silica-installed redox nanoparticle to suppress inflammatory bowel disease

Chronic inflammatory diseases such as inflammatory bowel diseases (IBD), which are strongly related to the overproduction of reactive oxygen species (ROS), have become more threatening to health. Silymarin is an active compound with the effect of expressing anti-inflammatory activity; however, it exhibits poor bioavailability due to the rapid metabolism and secretion, low permeability across the intestinal epithelial cells, and poor water solubility. In this study, we developed silica-containing redox nanoparticles (siRNP) with 50-60 nm in diameter to improve the bioavailability of silymarin by improving its uptake into the bloodstream and delivery to the targeted tissues of the colon. Silymarin-loaded siRNP (SM@siRNP) significantly increased the antioxidant capacity and anti-inflammatory efficacy in vitro by scavenging 2,2-diphenyl-1-picrylhydrazyl free radical and suppressing nitric oxide and pro-inflammatory cytokines as compared to the other treatments such as free silymarin, siRNP, and silymarin-loaded si-nRNP (the control nanoparticle without ROS scavenging property). Orally administered SM@siRNP significantly improved the bioavailability of silymarin and its retention in the colonic mucosa. The anti-inflammatory effects of SM@siRNP were also investigated in dextran sodium sulfate (DSS)-induced colitis in mice and it was observed that SM@siRNP treatment significantly improved the damage in the colonic mucosa of DSS colitis mice as compared to the other treatments. The results in this study indicate that SM@siRNP is a promising nanomedicine for enhancing the anti-inflammatory activity of silymarin and has a high potential for the treatment of IBD.

The Lord of the NanoRings: Cyclodextrins and the battle against SARS-CoV-2

A handful of singular structures and laws can be observed in nature. They are not always evident but, once discovered, it seems obvious how to take advantage of them. In chemistry, the discovery of reproducible patterns stimulates the imagination to develop new functional materials and technological or medical applications. Two clear examples are helical structures at different levels in biological polymers as well as ring and spherical structures of different size and composition. Rings are intuitively observed as holes able to thread elongated structures. A large number of real and fictional stories have rings as inanimate protagonists. The design, development or just discovering of a special ring has often been taken as a symbol of power or success. Several examples are the Piscatory Ring wore by the Pope of the Catholic Church, the NBA Championship ring and the One Ring created by the Dark Lord Sauron in the epic story The Lord of the Rings. In this work, we reveal the power of another extremely powerful kind of rings to fight against the pandemic which is currently affecting the whole world. These rings are as small as ~1 nm of diameter and so versatile that they are able to participate in the attack of viruses, and specifically SARS-CoV-2, in a large range of different ways. This includes the encapsulation and transport of specific drugs, as adjuvants to stabilize proteins, vaccines or other molecules involved in the infection, as cholesterol trappers to destabilize the virus envelope, as carriers for RNA therapies, as direct antiviral drugs and even to rescue blood coagulation upon heparin treatment.

“One ring to rule them all. One ring to find them. One ring to bring them all and in the darkness bind them.” J. R. R. Tolkien.

COVID-19: A Recommendation to Examine the Effect of Mouthrinses with β-Cyclodextrin Combined with Citrox in Preventing Infection and Progression

Considered to be a major portal of entry for infectious agents, the oral cavity is directly associated with the evolutionary process of SARS-CoV-2 in its inhalation of ambient particles in the air and in expectorations. Some new generations of mouth rinses currently on the market have ingredients that could contribute to lower the SARS-CoV-2 viral load, and thus facilitate the fight against oral transmission. If chlorhexidine, a usual component of mouth rinse, is not efficient to kill SARS-CoV-2, the use of a mouth rinses and/or with local nasal applications that contain β-cyclodextrins combined with flavonoids agents, such as Citrox, could provide valuable adjunctive treatment to reduce the viral load of saliva and nasopharyngeal microbiota, including potential SARS-CoV-2 carriage. We urge national agencies and authorities to start clinical trials to evaluate the preventive effects of βCD-Citrox therapeutic oral biofilm rinses in reducing the viral load of the infection and possibly disease progression.

Development and Evaluation of Antimicrobial and Modulatory Activity of Inclusion Complex of Euterpe oleracea Mart Oil and β-Cyclodextrin or HP-β-Cyclodextrin

The development of inclusion complexes is used to encapsulate nonpolar compounds and improve their physicochemical characteristics. This study aims to develop complexes made up of Euterpe oleracea Mart oil (EOO) and β-cyclodextrin (β-CD) or hydroxypropyl-β-cyclodextrin (HP-β-CD) by either kneading (KND) or slurry (SL). Complexes were analyzed by molecular modeling, Fourier-transform infrared spectroscopy, scanning electron microscopy, powder X-ray diffraction, thermogravimetry analysis and differential scanning calorimetry. The antibacterial activity was expressed as Minimum Inhibitory Concentration (MIC), and the antibiotic resistance modulatory activity as subinhibitory concentration (MIC/8) against Escherichia coli, Streptomyces aureus, Pseudomonas aeruginosa and Enterococcus faecalis. Inclusion complexes with β-CD and HP-β-CD were confirmed, and efficiency was proven by an interaction energy between oleic acid and β-CD of -41.28 ± 0.57 kJ/mol. MIC values revealed higher antibacterial activity of complexes compared to the isolated oil. The modulatory response of EOO and EOO-β-CD prepared by KND as well as of EOO-β-CD and EOO-HP-β-CD prepared by SL showed a synergistic effect with ampicillin against E. coli, whereas it was not significant with the other drugs tested, maintaining the biological response of antibiotics. The antimicrobial response exhibited by the complexes is of great significance because it subsidizes studies for the development of new pharmaceutical forms.

Supramolecular cyclodextrin complex: Diversity, safety, and applications in ocular therapeutics

Approximately 30-70% of the existing and new chemical entities exhibit poor aqueous solubility. For topical ocular delivery, drug molecules need to possess both hydrophilic and lipophilic nature to enable absorption through the aqueous tear layer and permeation through the corneal lipophilic barrier. To overcome the aqueous solubility related issues, various techniques such as solid dispersion, particle size reduction, cyclodextrin complexation, co-solvency, prodrug, derivatization, and salt formation are being explored in the healthcare sector. Cyclodextrin inclusion complexation techniques have been established by several pharmaceutical industries for systemic administration allowing a transition from the lab to the clinics. Though cyclodextrins are exploited in ocular drug delivery, there are prevailing concerns regarding its absorption enhancing capacity and mechanism, retention at the ocular surfaces and, irritation and toxicity profiles. In the present review, the efforts taken by various research groups to address the concerns of using cyclodextrin and its derivatives in ocular therapeutics are summarized. Also, considerations and utility of cyclodextrin systems in fabricating newer formulations such as contact lens, inserts, and implants have been discussed in the review.

Supramolecular Chemistry and Self-Organization: A Veritable Playground for Catalysis

The directed assembly of molecular building blocks into discrete supermolecules or extended supramolecular networks through noncovalent intermolecular interactions is an ongoing challenge in chemistry. This challenge may be overcome by establishing a hierarchy of intermolecular interactions that, in turn, may facilitate the edification of supramolecular assemblies. As noncovalent interactions can be used to accelerate the reaction rates and/or to increase their selectivity, the development of efficient and practical catalytic systems, using supramolecular chemistry, has been achieved during the last few decades. However, between discrete and extended supramolecular assemblies, the newly developed “colloidal tectonics” concept allows us to link the molecular and macroscopic scales through the structured engineering of colloidal structures that can be applied to the design of predictable, versatile, and switchable catalytic systems. The main cutting-edge strategies involving supramolecular chemistry and self-organization in catalysis will be discussed and compared in this review.

Alpha-cyclodextrin inhibits cholesterol crystal-induced complement-mediated inflammation: A potential new compound for treatment of atherosclerosis

BACKGROUND AND AIMS

Cholesterol crystal (CC)-induced inflammation is a critical step in the development of atherosclerosis. CCs activate the complement system and induce an inflammatory response resulting in phagocytosis of the CCs, production of reactive oxygen species (ROS) and release of cytokines. The cyclodextrin 2-hydroxypropyl-β-cyclodextrin has been found to reduce CC-induced complement activation and induce regression of established atherosclerotic plaques in a mouse model of atherosclerosis, thus inhibition of complement with cyclodextrins is a potential new strategy for treatment of inflammation during atherosclerosis. We hypothesized that other cyclodextrins, like α-cyclodextrin, may have related functions.

METHODS

The effect of cyclodextrins on CC-induced complement activation, phagocytosis, and production of ROS from granulocytes and monocytes was investigated by flow cytometry and ELISA.

RESULTS

We showed that α-cyclodextrin strongly inhibited CC-induced complement activation by inhibiting binding of the pattern recognition molecules C1q (via IgM) and ficolin-2. The reduced CC-induced complement activation mediated by α-cyclodextrin resulted in reduced phagocytosis and reduced ROS production in monocytes and granulocytes. Alpha-cyclodextrin was the most effective inhibitor of CC-induced complement activation, with the reduction in deposition of complement activation products being significantly different from the reduction induced by 2-hydroxypropyl-β-cyclodextrin. We also found that α-cyclodextrin was able to dissolve CCs.

CONCLUSIONS

This study identified α-cyclodextrin as a potential candidate in the search for therapeutics to prevent CC-induced inflammation in atherosclerosis.

Bowl-in-bowl complex formation with mixed sized calixarenes: adaptivity towards guest binding

We demonstrated the organization of two differently sized calixarenes C-methylresorcin[4]arene (RsC1) and either calix[6]arene (Calix6) or calix[8]arene (Calix8), where the lower rim of RsC1 partially overlaps with the upper rim of Calix6 or Calix8. An adaptive nature of the heteromacrocyclic assembly towards the binding of a model guest has been observed.

Hydroxypropyl-β-cyclodextrin-containing hydrogel enhances skin formononetin permeation/retention

OBJECTIVES

This study was aimed to investigate the in vitro permeation potential of hydrogel formulations containing the isoflavones formononetin and biochanin A and cyclodextrins in different combinations.

METHODS

The permeation assay was performed using porcine skin discs on Franz diffusion cells model. The isoflavone contents of the formulations were quantified in the different layers of the skin using a validated HPLC-PDA method.

KEY FINDINGS

The isoflavones individually incorporated into the formulations showed high permeation potential, especially formononetin, after the incorporation of hydroxypropyl-β-cyclodextrin that enhanced its permeation in the epidermis and dermis. Biochanin A showed 2.7 times of permeation capacity in the epidermis and dermis mainly after incorporation of cyclodextrins in the formulations. Formononetin showed reduction in its permeation when incorporated in the formulations together to biochanin A, showing the absence of synergism.

CONCLUSIONS

Our results indicated a noticeable skin permeation promoting effect of HPβCD in formononetin formulation. Furthermore, formononetin and biochanin A can permeate the skin being mostly retained in the epidermis and dermis, revealing its potential use in cosmetic preparations intended to prevent skin aging.

Improved Biopharmaceutical Properties of Oral Formulations of 1,2,4-Thiadiazole Derivative with Cyclodextrins: in Vitro and in Vivo Evaluation

The synthesized 1,2,4-thiadiazole derivative displaying biological activity has low aqueous solubility and dissolution rate. Novel oral formulations of thiadiazole with β- and hydroxypropyl-β-cyclodextrins were obtained by grinding and freeze-drying methods with the purpose to improve the aqueous solubility. Complex formation of 1,2,4-thiadiazole derivative with cyclodextrins was confirmed by means of solid-state ¹³C MAS CP/TOSS NMR. Solubility, dissolution rate and permeability of the solid inclusion complexes were evaluated in different biorelevant media (SGF, FaSSGF, FaSSIF) simulating the conditions in the gastrointestinal tract. It was demonstrated that the content of biorelevant media affects the properties of the inclusion complexes. In particular, solubilizing effect of cyclodextrins became less pronounced when the micelles of taurocholic acid and lecithin are formed in the dissolution media. The inclusion of thiadiazole into cyclodextrin cavity is in competition with its partitioning into the micelles and this should be taken into account when the in vivo behavior is predicted. The results of in vitro and in vivo experiments were found to be in agreement and showed the highest solubility, dissolution rate and bioavailability of the freeze-dried complexes of thiadiazole with hydroxypropyl-β-cyclodextrin. These complexes can be proposed as more effective dosage forms for oral administration.

Cyclodextrins improving the physicochemical and pharmacological properties of antidepressant drugs: a patent review

INTRODUCTION

Depression is a serious mood disorder and is one of the most common mental illnesses. Despite the availability of several classes of antidepressants, a substantial percentage of patients are unresponsive to these drugs, which have a slow onset of action in addition to producing undesirable side effects. Some scientific evidence suggests that cyclodextrins (CDs) can improve the physicochemical and pharmacological profile of antidepressant drugs (ADDs). The purpose of this paper is to disclose current data technology prospects involving antidepressant drugs and cyclodextrins.

AREAS COVERED

We conducted a patent review to evaluate the antidepressive activity of the compounds complexed in CDs, and we analyzed whether these complexes improved their physicochemical properties and pharmacological action. The present review used 8 specialized patent databases for patent research, using the term 'cyclodextrin' combined with 'antidepressive agents' and its related terms. We found 608 patents. In the end, considering the inclusion criteria, 27 patents reporting the benefits of complexation of ADDs with CDs were included.

EXPERT OPINION

The use of CDs can be considered an important tool for the optimization of physicochemical and pharmacological properties of ADDs, such as stability, solubility and bioavailability.

Effect of surface organic coatings of cellulose nanocrystals on the viability of mammalian cell lines

Cellulose nanocrystals (CNCs) have emerged as promising candidates for a number of bio-applications. Surface modification of CNCs continues to gain significant research interest as it imparts new properties to the surface of the nanocrystals for the design of multifunctional CNCs-based materials. A small chemical surface modification can potentially lead to drastic behavioral changes of cell-material interactions thereby affecting the intended bio-application. In this work, unmodified CNCs were covalently decorated with four different organic moieties such as a diaminobutane fragment, a cyclic oligosaccharide (β-cyclodextrin), a thermoresponsive polymer (poly[N-isopropylacrylamide]), and a cationic aminomethacrylamide-based polymer using different synthetic covalent methods. The effect of surface coatings of CNCs and the respective dose-response of the above organic moieties on the cell viability were evaluated on mammalian cell cultures (J774A.1 and MFC-7), using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphe-nyltetrazolium bromide and lactate dehydrogenase assays. Overall, the results indicated that cells exposed to surface-coated CNCs for 24 h did not display major changes in cell viability, membrane permeability as well as cell morphology. However, with longer exposure, all these parameters were somewhat affected, which appears not to be correlated with either anionic or cationic surface coatings of CNCs used in this study.