Cyclodextrin-membrane interaction in drug delivery and membrane structure maintenance

Advances in the use of local anesthetic extended-release systems in pain management

Pain management remains among the most common and largely unmet clinical problems today. Local anesthetics play an indispensable role in pain management. The main limitation of traditional local anesthetics is the limited duration of a single injection. To address this problem, catheters are often placed or combined with other drugs in clinical practice to increase the time that local anesthetics act. However, this method does not meet the needs of clinical analgesics. Therefore, many researchers have worked to develop local anesthetic extended-release types that can be administered in a single dose. In recent years, drug extended-release systems have emerged dramatically due to their long duration and efficacy, providing more possibilities for the application of local anesthetics. This paper summarizes the types of local anesthetic drug delivery systems and their clinical applications, discusses them in the context of relevant studies on local anesthetics, and provides a summary and outlook on the development of local anesthetic extended-release agents.

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.

Polymerized cyclodextrin microparticles for sustained antibiotic delivery in lung infections

Pulmonary infections complicate chronic lung diseases requiring attention to both the pathophysiology and complexity associated with infection management. Patients with cystic fibrosis (CF) struggle with continuous bouts of pulmonary infections, contributing to lung destruction and eventual mortality. Additionally, CF patients struggle with airways that are highly viscous, with accumulated mucus creating optimal environments for bacteria colonization. The unique physiology and altered airway environment provide an ideal niche for bacteria to change their phenotype often becoming resistant to current treatments. Colonization with multiple pathogens at the same time further complicate treatment algorithms, requiring drug combinations that can challenge CF patient tolerance to treatment. The goal of this research initiative was to explore the utilization of a microparticle antibiotic delivery system, which could provide localized and sustained antibiotic dosing. The outcome of this work demonstrates the feasibility of providing efficient localized delivery of antibiotics to manage infection using both preclinical in vitro and in vivo CF infection models. The studies outlined in this manuscript demonstrate the proof-of-concept and unique capacity of polymerized cyclodextrin microparticles to provide site-directed management of pulmonary infections.

Exploring the influence of microstructure and phospholipid type of liposomes on their interaction with lung

Liposome is a promising carrier for pulmonary drug delivery and the nano-sized liposomes have been widely investigated in the treatment of lung diseases. However, there still lack the knowledge of micron-sized liposomes for lung delivery, which have more advantages in terms of drug loading and sustained drug release capacity. The micron-sized liposomes can be classified into multilamellar liposome (MLL) and multivesicular liposome (MVL) according to their microstructure, thus, this study focused on exploring how the micron-sized liposomes with different microstructure and phospholipid composition influence their interaction with the lung. The MLL and MVL were prepared from different types of phospholipids (including soya phosphatidylcholine (SPC), egg yolk phosphatidylcholine (EPC), and dipalmitoyl phosphatidylcholine (DPPC)) with geometric diameter around 5 μm, and their in vitro pulmonary cell uptake, in vivo lung retention and organ distribution were investigated. The results showed that the microstructure of liposomes didn't affect pulmonary cellular uptake, in vivo lung retention and organ distribution. MLL and MVL prepared with the same phospholipid had similar cellular uptake in both NR8383 cells and A549 cells, and both of them possessed prolonged lung retention and limited distribution in other organs during 72 h. Notably, the phospholipid type presented remarkable influence on liposomes' interaction with the lung. SPC-based liposomes exhibited higher cellular uptake than the DPPC-based ones in both NR8383 cells and A549 cells, also possessed a better lung retention behavior. In conclusion, this study might provide theoretical knowledge for designing micron-sized liposomes intended for lung delivery.

Novel nano-encapsulated limonene: Utilization of drug-in-cyclodextrin-in-liposome formulation to improve the stability and enhance the antioxidant activity

Drug-in-cyclodextrin-in-liposome (DCL) combines advantages of cyclodextrin and liposome. Here, DCL formulation was successfully prepared to encapsulate limonene (Lim), whose characterization revealed that particle size was 147.5 ± 1.3 nm and zeta potential was -48.7 ± 0.8 mV. And the complexation mechanism of Lim/HP-β-CD inclusion complex (the intermediate of DCL) was analyzed by molecular dynamics simulation, showing that Lim was entrapped into the cavity of HP-β-CD through electrostatic and hydrophobic interaction with a molar ratio of 1:1. Notably, DCL formulation not only reduced Lim volatilization in 25℃, but also enhanced the free radical (DPPH· and ABTS·+) scavenging ability of Lim. In summary, Lim-DCL formulation improved the stability and enhanced the antioxidant activity of Lim. DCL nanocarrier system is suitable to preserve volatile and hydrophobic compounds, enlarging their application in pharmaceutics industries.

Asymmetric Lipid Bilayers and Potassium Channels Embedded Therein in the Contact Bubble Bilayer

Cell membranes are highly intricate systems comprising numerous lipid species and membrane proteins, where channel proteins, lipid molecules, and lipid bilayers, as continuous elastic fabric, collectively engage in multi-modal interplays. Owing to the complexity of the native cell membrane, studying the elementary processes of channel-membrane interactions necessitates a bottom-up approach starting from forming simplified synthetic membranes. This is the rationale for establishing an in vitro membrane reconstitution system consisting of a lipid bilayer with a defined lipid composition and a channel molecule. Recent technological advancements have facilitated the development of asymmetric membranes, and the contact bubble bilayer (CBB) method allows single-channel current recordings under arbitrary lipid compositions in asymmetric bilayers. Here, we present an experimental protocol for the formation of asymmetric membranes using the CBB method. The KcsA potassium channel is a prototypical model channel with huge structural and functional information and thus serves as a reporter of membrane actions on the embedded channels. We demonstrate specific interactions of anionic lipids in the inner leaflet. Considering that the local lipid composition varies steadily in cell membranes, we `present a novel lipid perfusion technique that allows rapidly changing the lipid composition while monitoring the single-channel behavior. Finally, we demonstrate a leaflet perfusion method for modifying the composition of individual leaflets. These techniques with custom synthetic membranes allow for variable experiments, providing crucial insights into channel-membrane interplay in cell membranes.

Cyclodextrins permeabilize DPPC liposome membranes: a focus on cholesterol content, cyclodextrin type, and concentration

Cyclodextrins (CDs) are known for their ability to extract lipid components from synthetic and biological membranes and therefore to induce an increase of membrane permeability. However, the effect of cholesterol (CHOL) content in the membrane on the CD permeabilizing effect was not considered yet. Given that an increase in CHOL content reduces the membrane permeability, the aim of this work was to reveal how CHOL would modulate the CDs effect on the membrane. Hence, liposomes made of dipalmitoyl phosphatidylcholine (DPPC) and various CHOL contents (DPPC/CHOL 100:10, 100:25, 100:50, and 100:100) encapsulating the hydrophilic fluorophore, sulforhodamine B (SRB), were prepared and exposed to the native CDs (α-CD, β-CD, γ-CD) and four β-CD derivatives: the randomly methylated-β-CD (RAMEB), the low methylated-β-CD (CRYSMEB), the hydroxypropyl-β-CD (HP-β-CD) and the sulfobutyl ether-β-CD (SBE-β-CD) at different CD/DPPC molar ratios (1:1, 10:1, and 100:1). The membrane permeability was monitored following the release of SRB with time. The results demonstrated that the CDs effect on the membrane depends on the CD type, CD concentration, and membrane CHOL content. The investigated CDs exhibited an instantaneous permeabilizing effect promoting vesicle leakage of SRB from the various membranes; this effect increased with CDs concentration. Among the studied CDs, α-CD, β-CD, and RAMEB were the most permeabilizing CDs on the different membranes. Similar modifications of SRB release from the various liposomal formulations were obtained with HP-β-CD, CRYSMEB, and SBE-β-CD. γ-CD was the less potent CD in affecting the membrane permeability. The CDs effect also depended on the CHOL content: at the CD/DPPC molar ratio (100:1), RAMEB and β-CD considerably permeabilized the membrane of high CHOL content (50%, 100%) while the remaining CDs showed a decreasing permeabilizing effect upon CHOL content membrane increase.

Cyclodextrin-Coordinated Liposome-in-Gel for Transcutaneous Quercetin Delivery for Psoriasis Treatment

Psoriasis is a chronic inflammatory skin disease that is difficult to treat. Quercetin (QT) is a dietary flavonoid known for its anti-inflammatory effects and safe use in humans. However, the topical application of quercetin for psoriasis treatment presents a significant challenge due to its poor water solubility and low stability in semisolid preparations, where it tends to recrystallize. This work presents a novel liposome-in-gel formulation for the quercetin-based topical treatment of psoriasis. The quercetin-loading liposomes are stabilized by hydroxypropyl-β-cyclodextrin (HPCD), which interacts with phospholipids via hydrogen bonding to form a layer of an HPCD coating on the liposome interface, thus resulting in improved stability. Various analytical techniques, such as FTIR spectroscopy, Raman spectroscopy, and TEM, were used to characterize the molecular coordination patterns between cyclodextrin and liposomes. The results demonstrated that HPCD assisted the liposomes in interfacing with the matrix lipids and keratins of the stratum corneum, thereby enhancing skin permeability and promoting drug penetration and retention in the skin. The in vivo results showed that the topical QT HPCD-liposome-in-gel improved the treatment efficacy of psoriatic plaque compared to free QT. It alleviated the symptoms of skin thickening and downregulated proinflammatory cytokines, including TNF-α, IL-17A, and IL-1β. The results suggested that the HPCD-coordinated liposome-in-gel system could be a stable carrier for topical QT therapy with good potential in psoriasis treatment.

The Manufacturing and Characterisation of Eugenol-Enclosed Liposomes Produced by Microfluidic Method

In this study, liposomes enclosing eugenol were prepared using microfluidics. Two lipids-1,2-dimyristoyl-sn-glycero-3-phosphocholine, 18:0 (DSPC) and 2-dimyristoyl-sn-glycero-3-phosphocholine, 14:0 (DMPC)-and microfluidic chips with serpentine and Y-shaped micromixing designs were used for the liposomal formulation. Minimum bactericidal concentration (MBC) values indicated that eugenol was more effective against Gram-negative than Gram-positive bacteria. Four different flow-rate ratios (FRR 2:1, 3:1, 4:1, 5:1) were explored. All liposomes' encapsulation efficiency (EE) was determined: 94.34% for DSPC 3:1 and 78.63% for DMPC 5:1. The highest eugenol release of 99.86% was observed at pH 4, DMPC 3:1 (Y-shaped chip). Liposomes were physically stable at 4, 20 and 37 °C for 60 days as determined by their size, polydispersity index (PDI) and zeta potential (ZP). The most stable liposomes were observed at FRR 5:1 for DSPC. EE, stability, and eugenol release studies proved that the liposomal formulations produced can be used as delivery vehicles to increase food safety.

Microbe-Anode Interactions: Comparing the impact of genetic and material engineering approaches to improve the performance of microbial electrochemical systems (MES)

Microbial electrochemical systems (MESs) are a highly versatile platform technology with a particular focus on power or energy production. Often, they are used in combination with substrate conversion (e.g., wastewater treatment) and production of value-added compounds via electrode-assisted fermentation. This rapidly evolving field has seen great improvements both technically and biologically, but this interdisciplinarity sometimes hampers overseeing strategies to increase process efficiency. In this review, we first briefly summarize the terminology of the technology and outline the biological background that is essential for understanding and thus improving MES technology. Thereafter, recent research on improvements at the biofilm-electrode interface will be summarized and discussed, distinguishing between biotic and abiotic approaches. The two approaches are then compared, and resulting future directions are discussed. This mini-review therefore provides basic knowledge of MES technology and the underlying microbiology in general and reviews recent improvements at the bacteria-electrode interface.

The Role of Cyclodextrin in the Construction of Nanoplatforms: From Structure, Function and Application Perspectives

Cyclodextrins (CyDs) in nano drug delivery systems have received much attention in pursuit of good compatibility, negligible toxicity, and improved pharmacokinetics of drugs. Their unique internal cavity has widened the application of CyDs in drug delivery based on its advantages. Besides this, the polyhydroxy structure has further extended the functions of CyDs by inter- and intramolecular interactions and chemical modification. Furthermore, the versatile functions of the complex contribute to alteration of the physicochemical characteristics of the drugs, significant therapeutic promise, a stimulus-responsive switch, a self-assembly capability, and fiber formation. This review attempts to list recent interesting strategies regarding CyDs and discusses their roles in nanoplatforms, and may act as a guideline for developing novel nanoplatforms. Future perspectives on the construction of CyD-based nanoplatforms are also discussed at the end of this review, which may provide possible direction for the construction of more rational and cost-effective delivery vehicles.

Achievement of the Selectivity of Cytotoxic Agents against Cancer Cells by Creation of Combined Formulation with Terpenoid Adjuvants as Prospects to Overcome Multidrug Resistance

Oncological diseases are difficult to treat even with strong drugs due to development the multidrug resistance (MDR) of cancer cells. A strategy is proposed to increase the efficiency and selectivity of cytotoxic agents against cancer cells to engage the differences in the morphology and microenvironment of tumor and healthy cells, including the pH, membrane permeability, and ion channels. Using this approach, we managed to develop enhanced formulations of cytotoxic agents with adjuvants (which are known as efflux inhibitors and as ion channel inhibitors in tumors)-with increased permeability in A549 and a protective effect on healthy HEK293T cells. The composition of the formulation is as follows: cytotoxic agents (doxorubicin (Dox), paclitaxel (Pac), cisplatin) + adjuvants (allylbenzenes and terpenoids) in the form of inclusion complexes with β-cyclodextrin. Modified cyclodextrins make it possible to obtain soluble forms of pure substances of the allylbenzene and terpenoid series and increase the solubility of cytotoxic agents. A comprehensive approach based on three methods for studying the interaction of drugs with cells is proposed: MTT test-quantitative identification of surviving cells; FTIR spectroscopy-providing information on the molecular mechanisms inaccessible to study by any other methods (including binding to DNA, surface proteins, or lipid membrane); confocal microscopy for the visualization of observed effects of Dox accumulation in cancer or healthy cells depending on the drug formulation as a direct control of the correctness of interpretation of the results obtained by the two other methods. We found that eugenol (EG) and apiol increase the intracellular concentration of cytostatic in A549 cells by 2-4 times and maintain it for a long time. However, an important aspect is the selectivity of the enhancing effect of adjuvants on tumor cells in relation to healthy ones. Therefore, the authors focused on adjuvant's effect on the control healthy cells (HEK293T): EG and apiol demonstrate "protective" properties from cytostatic penetration by reducing intracellular concentrations by about 2-3 times. Thus, a combined formulation of cytostatic drugs has been found, showing promise in the aspects of improving the efficiency and selectivity of antitumor drugs; thereby, one of the perspective directions for overcoming MDR is suggested.

Ensembles of carboxymethyl cyclodextrins on cationic liposomes as highly efficient nanocontainers for the delivery of hydrophobic compounds

The increase of payload is one of the key tasks in creation of nanocontainers for the delivery of bioactive substances (BAS). In this work the adsorption of anionic carboxymethyl cyclodextrins (CMCDs) on the surface of cationic liposomes was studied as mechanism of formation of capacious nanocontainers for the encapsulation and delivery of hydrophobic BAS. The formation and physico-chemical characteristics of complexes were studied by means of laser microelectrophoresis, dynamic light-scattering, conductometry and atomic force microscopy (AFM). As a model, bioactive molecule hydrophobic curcumin was chosen for the investigation. The encapsulation of curcumin was controlled by UV-Vis spectrometry. Interaction of CMCDs/liposomes complexes with model cell membranes was visualized by fluorescent microscopy. Finally, cytotoxicity of nanocontainers was studied by MTT-test. It was estimated that colloid stable complexes with net positive charge could contain up to 2.5÷5 CMCD molecules per one cationic lipid. Incorporation of curcumin in CMCDs does not change the character of interaction of oligosaccharides with liposomal membranes of individual liposome. CMCDs/liposomes complexes adsorb on model cell membranes without significant loss of CMCD molecules. This fact in addition to low cytotoxicity of cationic CMCDs/liposomes complexes demonstrates potential of their application as nanovehicles for the delivery of BAS.

Aided-efflux and high production of β-amyrin realized by β-cyclodextrin in situ synthesized on surface of Saccharomyces cerevisiae

As a plant-derived pentacyclic triterpenoid, β-amyrin has been heterogeneously synthesized in Saccharomyces cerevisiae. However, β-amyrin is intracellularly produced in a lower gram scale using recombinant S. cerevisiae, which limits the industrial applications. Although many strategies have been proven to be effective to improve the production of β-amyrin, the intracellularly accumulation is still a challenge in reaching higher titer and simplifying the extraction process. To solve this problem, the amphiphilic β-cyclodextrin (β-CD) has been previously employed to aid the efflux of β-amyrin out of the cells. Nevertheless, the supplemented β-CD in the medium is not consistent with β-amyrin synthesis and has the disadvantage of rather high cost. Therefore, an aided-efflux system based on in situ synthesis of β-CD was developed in this study to enhance the biosynthesis of β-amyrin and its efflux. The in situ synthesis of β-CD was started from starch by the surface displayed cyclodextrin glycosyltransferase (CGTase) on yeast cells. As a result, the synthesized β-CD could capture 16% of the intracellular β-amyrin and improve the total production by 77%. Furthermore, more strategies including inducing system remodeling, precursor supply enhancement, two-phase fermentation and lipid synthesis regulation were employed. Finally, the production of β-amyrin was increased to 73 mg/L in shake flask, 31 folds higher than the original strain, containing 31 mg/L of extracellular β-amyrin. Overall, this work provides novel strategies for the aided-efflux of natural products with high hydrophobicity in engineered S. cerevisiae.

An Overview of Taste-Masking Technologies: Approaches, Application, and Assessment Methods

It is well-known that plenty of active pharmaceutical ingredients (API) inherently possess an unpleasant taste, which influences the acceptance of patients, especially children. Therefore, manufacturing taste-masked dosage forms has attracted a lot of attention. This review describes in detail the taste-masking technologies based on the difference in the taste transmission mechanism which is currently available. In particular, the review highlights the application of various methods, with a special focus on how to screen the appropriate masking technology according to the properties of API. Subsequently, we overviewed how to assess taste-masking efficacy, guiding researchers to rationally design taste-masking formulations.

Cyclodextrins and Their Polymers Affect the Lipid Membrane Permeability and Increase Levofloxacin’s Antibacterial Activity In Vitro

Cyclodextrins (CDs) are promising drug carriers that are used in medicine. We chose CDs with different substituents (polar/apolar, charged/neutral) to obtain polymers (CDpols) with different properties. CDpols are urethanes with average Mw of ~120 kDa; they form nanoparticles 100–150 nm in diameter with variable ζ-potential. We studied the interaction of CD and CDpols with model (liposomal) and bacterial membranes. Both types of CD carriers cause an increase in the liposomal membrane permeability, and for polymers, this effect was almost two times stronger. The formation of CD/CDpols complexes with levofloxacin (LV) enhances LV’s antibacterial action 2-fold in vitro on five bacterial strains. The most pronounced effect was determined for LV-CD complexes. LV-CDs and LV-CDpols adsorb on bacteria, and cell morphology influences this process dramatically. According to TEM studies, the rough surface and proteinaceous fimbria of Gram-negative E. coli facilitate the adsorption of CD particles, whereas the smooth surface of Gram-positive bacteria impedes it. In comparison with LV-CDs, LV-CDpols are adsorbed 15% more effectively by E. coli, 2.3-fold better by lactobacilli and 5-fold better in the case of B. subtilis. CDs and CDpols are not toxic for bacterial cells, but may cause mild defects that, in addition to LV-CD carrier adsorption, improve LV’s antibacterial properties.

Exploring In Vitro Biological Cellular Responses of Pegylated β-Cyclodextrins

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.

Tetraethylenepentamine-Coated β Cyclodextrin Nanoparticles for Dual DNA and siRNA Delivery

Nucleic acid reagents, including plasmid-encoded genes and small interfering RNA (siRNA), are promising tools for validating gene function and for the development of therapeutic agents. Native β-cyclodextrins (BCDs) have limited efficiency in gene delivery due to their instable complexes with nucleic acid. We hypothesized that cationic BCD nanoparticles could be an efficient carrier for both DNA and siRNA. Tetraethylenepentamine-coated β-cyclodextrin (TEPA-BCD) nanoparticles were synthesized, characterized, and evaluated for targeted cell delivery of plasmid DNA and siRNA. The cationic TEPA coating provided ideal zeta potential and effective nucleic acid binding ability. When transfecting plasmid encoding green fluorescent protein (GFP) by TEPA-BCD, excellent GFP expression could be achieved in multiple cell lines. In addition, siRNA transfected by TEPA-BCD suppressed target GFP gene expression. We showed that TEPA-BCD internalization was mediated by energy-dependent endocytosis via both clathrin-dependent and caveolin-dependent endocytic pathways. TEPA-BCD nanoparticles provide an effective means of nucleic acid delivery and can act as potential carriers in future pharmaceutical application.

Comparing deep eutectic solvents and cyclodextrin complexes as curcumin vehicles for blue-light antimicrobial photodynamic therapy approaches

Curcumin (Cur), a polyphenolic compound derived from Curcuma longa L., has garnered the attention of the scientific community due to its remarkable biological properties such as its potential as a photosensitizing agent for photodynamic therapy (PDT). However, due to its low solubility in aqueous media and instability at physiological and alkaline pH, Cur has struggled to find relevant clinical application. To tackle these shortcomings, two distinct Cur-based formulations based on either complexation with methyl-β-cyclodextrin (MβCD), MβCDC-Cur, or dissolution in a choline chloride (ChCl): glycerol (Gly) deep eutectic solvent (DES), DES-Cur, were produced, physio-chemically characterized and compared regarding their potential as phototherapeutic agents for blue-light antimicrobial photodynamic therapy (aPDT) approaches. Both MβCD-Cur and DES-Cur were able to greatly enhance Cur solubility profile when compared to Cur powder. However, MβCD-Cur appears to hinder some of Cur's basal biological properties and possessed greater basal cytotoxicity towards L929 murine fibroblast cell line. Furthermore, MβCD-Cur was less photo-responsive when exposed to light which may hamper its application in blue-light aPDT approaches. In contrast, DES-Cur showed good biological properties and high photoresponsivity, displaying relevant phototoxicity against bacterial pathogens (≥ 99.9% bacterial reduction) while being better tolerated by L929 murine cells. Overall, this study found DES to be the more effective vehicle for Cur in terms of phototherapeutic potential which will serve as basis to develop novel platforms and approaches for blue-light aPDT targeting localized superficial infections.

Effect of β-cyclodextrin/polydopamine composite modified anode on the performance of microbial fuel cell

The relatively weak microbial adhesion is a bottleneck in improving the power generation performance of microbial fuel cell (MFC). Anode modification is a simple and effective method to solve this problem. A new type of β-cyclodextrin/polydopamine modified carbon felt anode was prepared, and the effects of β-cyclodextrin/polydopamine modified anode on the main performance indexes such as power density and chemical oxygen demand (COD) removal rate of MFC were evaluated. The maximum power density and the output electric energy during the test period of MFC using the modified anode were 102 mW/m² and 84.96 J, which were 364% and 295.3% higher than those of MFC with conventional carbon felt anode, respectively; and the COD removal rate was 124.4% higher than that of MFC with unmodified anode. Modifying the anode with β-cyclodextrin-polyacyclic composite materials is an effective method to improve the overall performance of MFC.

Development of oral curcumin based on pH-responsive transmembrane peptide-cyclodextrin derivative nanoparticles for hepatoma

Herein, a pH-responsive cyclodextrin derivative (R6H4-CMβCD) with cell-penetrating ability was successfully synthesized, and curcumin-loaded nanoparticles (R6H4-CMβCD@CUR NPs, RCCNPs) were developed to improve its efficacy in hepatoma. RCCNPs could improve the cell uptake compared with CMβCD@CUR NPs (CCNPs) and were internalized into cells mainly through endocytosis mediated by reticulin and macropinocytosis. Furthermore, the accumulation of RCCNPs in hepatoma cells at pH 6.4 was higher than that at pH 7.4, indicating a pH-responsive uptake. Additionally, RCCNPs could escape from the lysosomes via the "proton sponge effect", and a high apoptosis rate was detected. Importantly, in vivo experiments revealed that orally administered RCCNPs could exert excellent anti-cancer effects in tumor-bearing mice. Hematoxylin-eosin staining did not show significant histological changes in the major organs. Thus, our findings indicate the potential of R6H4-CMβCD as a nanopharmaceutical material, and RCCNPs as an effective delivery system for oral curcumin in cancer management.

Application of molecular docking in elaborating molecular mechanisms and interactions of supramolecular cyclodextrin

The cyclodextrin (CD)-based supramolecular nanomedicines have attracted growing interest because of their superior characteristics, including desirable biocompatibility, low toxicity, unique molecular structure and easy functionalization. The smart structures of CD impart host-guest interaction for meeting the multifunctional needs of disease therapy. However, it faces challenges in formulation design and inclusion mechanism clarification of the functional supramolecular assemblies owing to the complicated structures and mechanisms. Fortunately, molecular docking helps the researchers to comprehend the interaction between the drug and the target molecule for achieving high-through screening from the database. In this review, we summarized the category and characteristics of molecular docking along with the properties and applications of CD. Significantly, we highlighted the application of molecular docking in elaborating molecular mechanisms and simulating complex structures at molecular levels. The issues and development of CD and molecular docking were also presented to provide beneficial reference and new insights for supramolecular nano-systems.

Effect of cysteamine hydrochloride-loaded liposomes on skin depigmenting and penetration

Skin hyperpigmentation is caused by an excessive production of melanin. Cysteamine, an aminothiol compound physiologically synthetized in human body cells, is known as depigmenting agent. The aim of this study was to evaluate the depigmenting activity and skin penetration of liposome formulations encapsulating cysteamine hydrochloride. First, cysteamine hydrochloride-loaded liposomes were prepared and characterized for their size, polydispersity index, zeta potential and the encapsulation efficiency of the active molecule. The stability of cysteamine hydrochloride in the prepared liposome formulations in suspension and freeze-dried forms was then assessed. The in vitro cytotoxicity of cysteamine and cysteamine-loaded liposome suspensions (either original or freeze-dried) was evaluated in B16 murine melanoma cells. The measurement of melanin and tyrosinase activities was assessed after cells treatment with free and encapsulated cysteamine. The antioxidant activity of the free and encapsulated cysteamine was evaluated by the measurement of ROS formation in treated cells. The ex vivo human skin penetration study was also performed using Franz diffusion cell. The stability of cysteamine hydrochloride was improved after encapsulation in liposomal suspension. In addition, for the liposome re-suspended after freeze-drying, a significant increase of vesicle stability was observed. The free and the encapsulated cysteamine in suspension (either original or freeze-dried) did not show any cytotoxic effect, inhibited the melanin synthesis as well as the tyrosinase activity. An antioxidant activity was observed for the free and the encapsulated cysteamine hydrochloride. The encapsulation enhanced the skin penetration of cysteamine hydrochloride. The penetration of this molecule was better for the re-suspended freeze-dried form than the original liposomal suspension where the drug was found retained in the epidermis layer of the skin.

Encapsulation of α-Pinene in Delivery Systems Based on Liposomes and Cyclodextrins

The essential oil component α-pinene has multiple biological activities. However, its application is limited owing to its volatility, low aqueous solubility, and chemical instability. For the aim of improving its physicochemical properties, α-pinene was encapsulated in conventional liposomes (CLs) and drug-in-cyclodextrin-in-liposomes (DCLs). Hydroxypropyl-β-cyclodextrin/α-pinene (HP-β-CD/α-pinene) inclusion complexes were prepared in aqueous solution, and the optimal solubilization of α-pinene occurred at HP-β-CD:α-pinene molar ratio of 7.5:1. The ethanol-injection method was applied to produce different formulations using saturated (Phospholipon 90H) or unsaturated (Lipoid S100) phospholipids in combination with cholesterol. The size, the phospholipid and cholesterol incorporation rates, the encapsulation efficiency (EE), and the loading rate (LR) of α-pinene were determined, and the storage stability of liposomes was assessed. The results showed that α-pinene was efficiently entrapped in CLs and DCLs with high EE values. Moreover, Lipoid S100 CLs displayed the highest LR (22.9 ± 2.2%) of α-pinene compared to the other formulations. Both carrier systems HP-β-CD/α-pinene inclusion complex and Lipoid S100 CLs presented a gradual release of α-pinene. Furthermore, the DPPH radical scavenging activity of α-pinene was maintained upon encapsulation in Lipoid S100 CLs. Finally, it was found that all formulations were stable after three months of storage at 4 °C.

Cyclodextrin-based Pickering emulsions: functional properties and drug delivery applications

Cyclodextrins (CDs) are biocompatible, cyclic oligosaccharides that are widely used in various industrial applications and have intriguing interfacial science properties. While CD molecules typically have low surface activity, they are capable of stabilizing emulsions by inclusion complexation of oil-phase components at the oil/water interface, which results in Pickering emulsion formation. Such surfactant-free formulations have gained considerable attention in recent years, owing to their enhanced physical stability, improved tolerability, and superior environmental compatibility compared to conventional, surfactant-based emulsions. In this review, we critically describe the latest insights into the molecular mechanisms involved in CD stabilization of Pickering emulsions, including covering practical aspects such as methods to prepare CD-based Pickering emulsions, lipid encapsulation, and relevant stability issues. In addition, the rheological and textural features of CD-based Pickering emulsions are discussed and particular attention is focused on promising examples for drug delivery, cosmetic, and nutraceutical applications. The functionality of currently developed CD-based Pickering emulsions is also summarised, including examples such as antifungal uses, and we close by discussing emerging possibilities to utilize the molecular encapsulation of CD-based emulsions for translational medicine applications in the antiviral and antibacterial spaces.

Mechanochemical preparation of chrysomycin A self-micelle solid dispersion with improved solubility and enhanced oral bioavailability

BACKGROUND

Chrysomycin A (CA) has been reported as numerous excellent biological activities, such as antineoplastic and antibacterial. Though, poor solubility of CA limited its application in medical field. Due to good amphiphilicity and potential anticancer effect of disodium glycyrrhizin (Na2GA) as an excipient, an amorphous solid dispersion (Na2GA/CA-BM) consisting of CA and Na2GA was prepared in the present study by mechanochemical technology (roll mill ML-007, zirconium balls, 30 rpm, 2.5 h) to improve the solubility and oral bioavailability of CA. Then, Na2GA/CA-BM was self-assembled to micelles in water. The interaction of CA and Na2GA in solid state were investigated by X-ray diffraction studies, polarized light microscopy, and scanning electron microscope. Meanwhile, the properties of the sample solution were analyzed by dynamic light scattering and transmission electron. Furthermore, the oral bioavailability and antitumor ability of Na2GA/CA-BM in vivo were tested, providing a theoretical basis for future application of CA on cancer therapy.

RESULTS

CA encapsulated by Na2GA was self-assembled to nano-micelles in water. The average diameter of nano-micelle was 131.6 nm, and zeta potential was - 11.7 mV. Three physicochemical detections showed that CA was transformed from crystal into amorphous form after treated with ball milling and the solubility increased by 50 times. Na2GA/CA-BM showed a significant increase of the bioavailability about two time that of free CA. Compared with free CA, the in-vivo antitumor studies also exhibited that Na2GA/CA-BM had an excellent inhibition of tumor growth.

CONCLUSIONS

Na2GA/CA-BM nanoparticles (131.6 nm, - 11.7 mV) prepared by simple and low-cost mechanochemical technology can improve oral bioavailability and antitumor efficacy of CA in vivo, suggesting a potential formulation for efficient anticancer treatment.

Incorporation of simvastatin into lipid membranes: Why deliver a statin in form of inclusion complex with hydrophilic cyclodextrin

In this work, the effects of simvastatin (SIM), (2-hydroxypropyl)-β-cyclodextrin (HPβCD) and their complex (SIM:HPβCD) on the structure and properties of lipid membranes were investigated for the first time by Langmuir technique combined with PM-IRRAS spectroscopy. An improved understanding of the differences of the interactions between free SIM, and SIM in the form of an inclusion complex with HPβCD with the lipid membrane will improve the development of preparation methods for in vivo applications. Monolayers of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), cholesterol (Chol) and their mixture DMPC:Chol (7:3) served as simple models of one leaflet of the cell membrane. The penetration of well-organized lipid layers by simvastatin lead to their fluidization but the extent of this unwanted effect was smaller when the drug was delivered in the form of the SIM:HPβCD complex. Surface pressure vs. time dependencies showed that the drug encapsulated with cyclodextrin dissociated from the complex upon contact with the lipid layer and the weak interactions between the exterior polar part of the HPβCD and the polar headgroups of the lipid layer facilitated smooth incorporation of the released lipophilic drug into the membrane. At a longer time-scale, the HPβCD ligand released from the complex removed some cholesterol, but not DMPC, from the lipid layer, hence, similarly to the enzyme inhibiting action of statins - it lead to the decrease of the amount of cholesterol in the membrane. Delivery of simvastatin in the form of an inclusion complex with HPβCD is proposed as an approach improving its bioavailability in the cholesterol-lowering therapies.

Biopolymer-liposome hybrid systems for controlled delivery of bioactive compounds: Recent advances

Conventional liposomes still face many challenges associated with the poor physical and chemical stability, considerable loss of encapsulated cargo, lack of stimulus responsiveness, and rapid elimination from blood circulation. Integration of versatile functional biopolymers has emerged as an attractive strategy to overcome the limitation of usage of liposomes. This review comprehensively summarizes the most recent studies (2015-2020) and their challenges aiming at the exploration of biopolymer-liposome hybrid systems, including surface-modified liposomes, biopolymer-incorporated liposomes, guest-in-cyclodextrin-in-liposome, liposome-in-hydrogel, liposome-in-film, and liposome-in-nanofiber. The physicochemical principles and key technical information underlying the combined strategies for the fabrication of polymeric liposomes, the advantages and limitations of each of the systems, and the stabilization mechanisms are discussed through various case studies. Special emphasis is directed toward the synergistic efficiencies of biopolymers and phospholipid bilayers on encapsulation, protection, and controlled delivery of bioactives (e.g., vitamins, carotenoids, phenolics, peptides, and other health-related compounds) for the biomedical, pharmaceutical, cosmetic, and functional food applications. The major challenges, opportunities, and possible further developments for future studies are also highlighted.

Enrofloxacin/florfenicol loaded cyclodextrin metal-organic-framework for drug delivery and controlled release

We presented an antibiotic-loaded γ-cyclodextrin metal-organic framework that delivered antibiotics suitable for the treatment of bacterial infections. The γ-cyclodextrin metal-organic framework was developed using γ-cyclodextrin and potassium ion via the ultrasonic method. The antibiotic (florfenicol and enrofloxacin) was primarily encapsulated into the pore structures of γ-CD-MOF, which allowed the sustained release of antibiotics over an extended period of time in vitro and in vivo. Notably, antibiotics-loaded γ-CD-MOF showed much superior activity against bacteria than free antibiotics (lower MIC value) and displayed better long-lasting activity (longer antibacterial time). The antibiotics-loaded γ-CD-MOF showed nontoxic and perfect biocompatibility to mammalian cells and tissues both in vitro and in vivo. These materials thus represent a novel drug-delivery device suitable for antibiotic therapy. This research is of great significance for reducing the generation of bacterial resistance and providing new ideas for the application of γ-CD-MOF.

B, Fejes Z, Fenyvesi F. Investigation of the Cellular Effects of Beta- Cyclodextrin Derivatives on Caco-2 Intestinal Epithelial Cells

Cyclodextrins are widely used excipients for increasing water-solubility, delivery and bioavailability of lipophilic drugs. By using fluorescent cyclodextrin derivatives, we showed previously that cyclodextrins are able to enter Caco-2 intestinal cells by endocytosis, but the influence of different fluorescent labeling on the same cyclodextrin derivative has not been studied. The consequences of the cellular internalization of cyclodextrins have not been revealed yet either. The aims of this study were to compare the cellular internalization of fluorescein- and rhodamine-labeled (2-hydroxypropyl)-, (HPBCD) and randommethyl-β-cyclodextrins (RAMEB) and to investigate the intracellular effects of these derivatives on Caco-2 cells. Stimulation of the NF-kappa B pathway and autophagy and localization of these derivatives in lysosomes were tested. The endocytosis of these derivatives was examined by fluorescence microscopy and flow cytometry. Both fluorescein- and rhodamine-labeled derivatives entered the cells, therefore the type of the fluorescent labeling did not influence their internalization. Cyclodextrin pretreatment did not activate the translocation of the p65 subunit of the NF-kappa B heterodimer into the cell nuclei from the cytoplasm. After HPBCD or RAMEB treatment, formation of the autophagosomes did not increase compared to the control sample and at the same time these derivatives could be detected in lysosomes after internalization.

3-O-Methylquercetin from Achyrocline satureioides-cytotoxic activity against A375-derived human melanoma cell lines and its incorporation into cyclodextrins-hydrogels for topical administration

3-O-Methylquercetin (3OMQ), a natural 3-O-methylflavonoid, was isolated from Achyrocline satureioides and purified using the high-performance counter current chromatography (HPCCC) on a semi-preparative scale. High-purity 3OMQ (98%) was obtained with excellent recovery (81.8% (w/w)) and good yield (190 mg/100 g of plant). Isolated 3OMQ was evaluated against the A375 human amelanotic melanoma cancer cell line and A375-derived with different degrees of aggressiveness (A375-A7, A375-G10, and A375-PCDNA3). The results showed that 3OMQ reduced the cell viability of all strains, demonstrating time- and dose-dependent responses. 3OMQ was used to obtain hydrogels for the topical treatment of melanoma. Thus, 3OMQ was incorporated into hypromellose hydrogels with/without different cyclodextrins (CDs). The 3OMQ formulations showed permeation/retention in all skin layers, namely stratum corneum, epidermis, and dermis. A significant amount of 3OMQ was found in the replication site of the melanoma cells (epidermis and dermis). Altogether, these results demonstrate that 3OMQ can be isolated from Achyrocline satureioides by HPCCC on a semi-preparative scale and exhibit cytotoxic activity against melanoma cells. Its incorporation into an HPMC hydrogel containing HP-β-CD yielded a formulation with excellent technological and biopharmaceutical characteristics for evaluating the topical management of melanoma.

Aerosolization Performance, Antitussive Effect and Local Toxicity of Naringenin-Hydroxypropyl-β-Cyclodextrin Inhalation Solution for Pulmonary Delivery

The aim of present study was to evaluate the feasibility of a naringenin-hydroxypropyl-β-cyclodextrin (naringenin-HPβCD) inhalation solution for pulmonary delivery. Naringenin, a flavanone derived from citrus fruits, has been proven to exhibit excellent peripheral antitussive effect. To address the limitation of its poor oral bioavailability and low local concentration in the lung, a naringenin-HPβCD inhalation solution was prepared for pulmonary delivery. The aerosolization performance of formulation was evaluated by next generation impactor (NGI). Both dose-dependent and time-dependent antitussive effects of naringenin-HPβCD inhalation solution on acute cough induced by citric acid in guinea pigs were investigated. In vitro toxicity of naringenin-HPβCD inhalation solution in pulmonary Calu-3 cells was evaluated by MTS assay, and in vivo local toxicity investigation was achieved by assessing bronchoalveolar lavage (BALF) and lung histology after a 7-day inhalation treatment in guinea pigs. Fine particle fraction (FPF) of the formulation was determined as 53.09%. After inhalation treatment of 15 min, naringenin-HPβCD inhalation solution within the studied range of 0.2-3.6 mg/kg could dose-dependently reduce the cough frequency with the antitussive rate of 29.42-39.42%. Naringenin-HPβCD inhalation solution in concentration range of 100-400 μM did not decrease cell viability of Calu-3 cells, and the maximum effective dose (3.6 mg/kg) was non-toxic during the short-term inhalation treatment for guinea pigs. In conclusion, naringenin-HPβCD inhalation solution was capable for nebulization and could provide rapid response with reduced dose for the treatment of cough.

PLGA Nanoparticle Platform for Trans-Ocular Barrier to Enhance Drug Delivery: A Comparative Study Based on the Application of Oligosaccharides in the Outer Membrane of Carriers

Purpose

The trans-ocular barrier is a key factor limiting the therapeutic efficacy of triamcinolone acetonide. We developed a poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) surface modified respectively with 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD), chitosan oligosaccharide and trehalose. Determination of the drug/nanoparticles interactions, characterization of the nanoparticles, in vivo ocular compatibility tests, comparisons of their corneal permeability and their pharmacokinetics in aqueous humor were carried out.

Methods

All PLGA NPs were prepared by the single emulsion and evaporation method and the drug-nanoparticle interaction was studied. The physiochemical features and in vitro corneal permeability of NPs were characterized while the aqueous humor pharmacokinetics was performed to evaluate in vivo corneal permeability of NPs. Ocular compatibility of NPs was investigated through Draize and histopathological test.

Results

The PLGA NPs with lactide/glycolide ratio of 50:50 and small particle size (molecular weight 10 kDa) achieved optimal drug release and corneal permeability. Surface modification with different oligosaccharides resulted in uniform particle sizes and similar drug-nanoparticle interactions, although 2-HP-β-CD/PLGA NPs showed the highest entrapment efficiency. In vitro evaluation and aqueous humor pharmacokinetics further revealed that 2-HP-β-CD/PLGA NPs had greater trans-ocular permeation and retention compared to chitosan oligosaccharide/PLGA and trehalose/PLGA NPs. No ocular irritation in vivo was detected after applying modified/unmodified PLGA NPs to rabbit's eyes.

Conclusion

2-HP-β-CD/PLGA NPs are a promising nanoplatform for localized ocular drug delivery through topical administration.

Chiral differentiation of l- and d-penicillamine by β-cyclodextrin: Investigated by IRMPD spectroscopy and theoretical simulations

The chirality of penicillamine (Peni) results in different clinic applications. Host-guest complex based drug delivery system that differentiates the two enantiomers and provides delayed release is of significance in medication. We hereby used β-CD to encapsulate d- and l-Peni. IRMPD spectra show different characteristic vibrations to distinguish the two enantiomers. Besides common peaks found at 3000-3100 cm^-1 and 3520 cm^-1, featured peaks are found around 2900 cm^-1 and 3400 cm^-1. It is found that the featured vibrations of [β-CD + l-Peni + H]⁺ are more red-shifted than those of [β-CD + d-Peni + H]⁺. Through DFT calculations on the complex configurations sampled from molecular dynamics simulations, d-Peni is found embedded inside β-CD with a lower free energy of 11.5 kJ mol^-1 in the lowest configuration than that of the lowest [β-CD + l-Peni + H]⁺ configuration, in which l-Peni is found lying upon the β-CD. The featured vibrational peaks are attributed to the specific NH⋯O, OH⋯O intermolecular hydrogen bonds. The red-shifted characteristic peaks of [β-CD + l-Peni + H]⁺ in IRMPD spectra owe to the stronger NH⋯O hydrogen bonds.

The Budesonide-Hydroxypropyl-β-Cyclodextrin Complex Attenuates ROS Generation, IL-8 Release and Cell Death Induced by Oxidant and Inflammatory Stress. Study on A549 and A-THP-1 Cells

Synthetic glucocorticoids such as budesonide (BUD) are potent anti-inflammatory drugs commonly used to treat patients suffering from chronic inflammatory diseases. A previous animal study reported a higher anti-inflammatory activity with a 2-hydroxypropyl-β-cyclodextrin (HPβCD)-based formulation of BUD (BUD:HPβCD). This study investigated, on cellular models (A549 and A-THP-1), the effect of BUD:HPβD in comparison with BUD and HPβCD on the effects induced by oxidative and inflammatory stress as well as the role of cholesterol. We demonstrated the protective effect afforded by BUD:HPβCD against cytotoxicity and ROS generation induced by oxidative and inflammatory stress. The effect observed for BUD:HPβCD was comparable to that observed with HPβCD with no major effect of cholesterol content. We also demonstrated (i) the involvement of the canonical molecular pathway including ROS generation, a decrease in PI3K/Akt activation, and decrease in phosphorylated/unphosphorylated HDAC2 in the effect induced by BUD:HPβCD, (ii) the maintenance of IL-8 decrease with BUD:HPβCD, and (iii) the absence of improvement in glucocorticoid insensitivity with BUD:HPβCD in comparison with BUD, in conditions where HDAC2 was inhibited. Resulting from HPβCD antioxidant and anticytotoxic potential and protective capacity against ROS-induced PI3K/Akt signaling and HDAC2 inhibition, BUD:HPβCD might be more beneficial than BUD alone in a context of concomitant oxidative and inflammatory stress.

Cisplatin-loaded albumin nanoparticle and study their internalization effect by using β-cyclodextrin

The present study with aim at enhancing the therapeutic and anti-cancer properties of cisplatin (CPT)-loaded bovine serum albumin (BSA) nanoparticles. The BSA nanoparticles containing CPT (CPT-BSANPs) were successfully prepared by the desolvation technique. The physicochemical characterization of the CPT-BSANPs were used by Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The particle size of CPT-BSANPs was found less than 200 nm with 75.02 ± 0.15% entrapment efficiency (EE), while zeta potential and PDI were -17.6 mV and 0.2, respectively. In vitro release behavior of the CPT from the carrier suggests that about 64% of the drug gets released after 48 hrs. The anti-cancer activities of the CPT-BSANPs were tested on MCF-7 cell lines. Our studies show that CPT-BSANPs nanoparticles showed specific targeting and enhanced cytotoxicity to MCF-7 cells when compared to the bare CPT. Thus results suggest that CPT-BSANPs fallowed caveolae-mediated endocytosis, it may become better option for intracellular delivery of anticancer drug.

Hydroxy-Propil-β-Cyclodextrin Inclusion Complexes of two Biphenylnicotinamide Derivatives: Formulation and Anti-Proliferative Activity Evaluation in Pancreatic Cancer Cell Models

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies, with poor outcomes largely due to its unique microenvironment, which is responsible for the low response to drugs and drug-resistance phenomena. This clinical need led us to explore new therapeutic approaches for systemic PDAC treatment by the utilization of two newly synthesized biphenylnicotinamide derivatives, PTA73 and PTA34, with remarkable antitumor activity in an in vitro PDAC model. Given their poor water solubility, inclusion complexes of PTA34 and PTA73 in Hydroxy-Propil-β-Cyclodextrin (HP-β-CD) were prepared in solution and at the solid state. Complexation studies demonstrated that HP-β-CD is able to form stable host–guest inclusion complexes with PTA34 and PTA73, characterized by a 1:1 apparent formation constant of 503.9 M⁻¹ and 369.2 M⁻¹, respectively (also demonstrated by the Job plot), and by an increase in aqueous solubility of about 150 times (from 1.95 µg/mL to 292.5 µg/mL) and 106 times (from 7.16 µg/mL to 762.5 µg/mL), in the presence of 45% w/v of HP-β-CD, respectively. In vitro studies confirmed the high antitumor activity of the complexed PTA34 and PTA73 towards PDAC cells, the strong G2/M phase arrest followed by induction of apoptosis, and thus their eligibility for PDAC therapy.

Investigation of Cytotoxicity and Cell Uptake of Cationic Beta-Cyclodextrins as Valid Tools in Nasal Delivery

Cyclodextrin polymers have high applicability in pharmaceutical formulations due to better biocompatibility, solubility enhancement, loading capacity and controlled drug release than their parent, cyclodextrins. The cytotoxicity and cell uptake of new cationic beta-cyclodextrin monomers and polymers were evaluated as suitable materials for nasal formulations and their protective effects on cells exposed to hydrogen peroxide were studied. PC12 and CACO-2 cells were selected as the neuronal- and epithelial-type cells, respectively, to mimic the structure of respiratory and olfactory epithelia of the nasal cavity. All cationic beta-cyclodextrin polymers tested showed dose- and time-dependent toxicity; nevertheless, at 5 µM concentration and 60 min of exposure, the quaternary-ammonium-beta-cyclodextrin soluble polymer could be recognized as nontoxic. Based on these results, a fluorescently labelled quaternary-ammonium-beta-cyclodextrin monomer and polymer were selected for uptake studies in CACO-2 cells. The monomeric and polymeric beta-cyclodextrins were internalized in the cytoplasm of CACO-2 cells; the cationic monomer showed higher permeability than the hydroxypropyl-beta-cyclodextrin, employed as comparison. Therefore, these cationic beta-cyclodextrins showed potential as excipients able to improve the nasal absorption of drugs. Furthermore, amino-beta-cyclodextrin and beta-cyclodextrin soluble polymers were able to reduce oxidative damage in PC12 and CACO-2 cells and thus could be studied as bioactive carriers or potential drugs for cell protection against oxidative stress.

Delivery of Alpha-Mangostin Using Cyclodextrins through a Biological Membrane: Molecular Dynamics Simulation

α-Mangostin (MGS) exhibits various pharmacological activities, including antioxidant, anticancer, antibacterial, and anti-inflammatory properties. However, its low water solubility is the major obstacle for its use in pharmaceutical applications. To increase the water solubility of MGS, complex formation with beta-cyclodextrins (βCDs), particularly with the native βCD and/or its derivative 2,6-dimethyl-β-CD (DMβCD) is a promising technique. Although there have been several reports on the adsorption of βCDs on the lipid bilayer, the release of the MGS/βCDs inclusion complex through the biological membrane remains unclear. In this present study, the release the MGS from the two different βCDs (βCD and DMβCD) across the lipid bilayer was investigated. Firstly, the adsorption of the free MGS, free βCDs, and inclusion complex formation was studied by conventional molecular dynamics simulation. The MGS in complex with those two βCDs was able to spontaneously release free MGS into the inner membrane. However, both MGS and DMβCD molecules potentially permeated into the deeper region of the interior membrane, whereas βCD only adsorbed at the outer membrane surface. The interaction between secondary rim of βCD and the 1-palmitoeyl-2-oleoyl-glycero-3-phosphocholine (POPC) phosphate groups showed the highest number of hydrogen bonds (up to 14) corresponding to the favorable location of βCD on the POPC membrane. Additionally, the findings suggested that electrostatic energy was the main driving force for βCD adsorption on the POPC membrane, while van der Waals interactions played a predominant role in DMβCD adsorption. The release profile of MGS from the βCDs pocket across the lipid bilayer exhibited two energy minima along the reaction coordinate associated with the permeation of the MGS molecule into the deeper region of the POPC membrane.

Liposomal membrane permeability assessment by fluorescence techniques: Main permeabilizing agents, applications and challenges

Liposomes are lipid vesicles made of one or multiple lipid bilayers surrounding an internal aqueous core. They are broadly employed as models to study membrane structure and properties. Among these properties, liposome membrane permeability is crucial and widely assessed by fluorescence techniques. The first part of this review is devoted to describe the various techniques used for membrane permeability assessment. Attention is paid to fluorescence techniques based on vesicle leakage of self-quenching probes, dye/quencher pair or cation/ligand pair. Secondly, the membrane-active agents inducing membrane permeabilization is presented and details on their mechanisms of action are given. Emphasis is also laid on the intrinsic and extrinsic factors that can modulate the membrane permeability. Hence, a suitable liposomal membrane should be formulated according to the aim of the study and its application.