Role of Cyclodextrins in Nanoparticle-Based Drug Delivery Systems

Quantum Dots as a Good Carriers of Unsymmetrical Bisacridines for Modulating Cellular Uptake and the Biological Response in Lung and Colon Cancer Cells

Nanotechnology-based drug delivery provides a promising area for improving the efficacy of cancer treatments. Therefore, we investigate the potential of using quantum dots (QDs) as drug carriers for antitumor unsymmetrical bisacridine derivatives (UAs) to cancer cells. We examine the influence of QD-UA hybrids on the cellular uptake, internalization (Confocal Laser Scanning Microscope), and the biological response (flow cytometry and light microscopy) in lung H460 and colon HCT116 cancer cells. We show the time-dependent cellular uptake of QD-UA hybrids, which were more efficiently retained inside the cells compared to UAs alone, especially in H460 cells, which could be due to multiple endocytosis pathways. In contrast, in HCT116 cells, the hybrids were taken up only by one endocytosis mechanism. Both UAs and their hybrids induced apoptosis in H460 and HCT116 cells (to a greater extent in H460). Cells which did not die underwent senescence more efficiently following QDs-UAs treatment, compared to UAs alone. Cellular senescence was not observed in HCT116 cells following treatment with both UAs and their hybrids. Importantly, QDgreen/red themselves did not provoke toxic responses in cancer or normal cells. In conclusion, QDs are good candidates for targeted UA delivery carriers to cancer cells while protecting normal cells from toxic drug activities.

Protective Effect of Natural Products against Huntington's Disease: An Overview of Scientific Evidence and Understanding Their Mechanism of Action

Huntington's disease (HD), a neurodegenerative disease, normally starts in the prime of adult life, followed by a gradual occurrence of characteristic psychiatric disturbances and cognitive and motor dysfunction. To the best of our knowledge, there is no treatment available to completely mitigate the progression of HD. Among various therapeutic approaches, exhaustive literature reports have confirmed the medicinal benefits of natural products in HD experimental models. Building on this information, this review presents a brief overview of the neuroprotective mechanism(s) of natural products against in vitro/in vivo models of HD. Relevant studies were identified from several scientific databases, including PubMed, ScienceDirect, Scopus, and Google Scholar. After screening through literature from 2005 to the present, a total of 14 medicinal plant species and 30 naturally isolated compounds investigated against HD based on either in vitro or in vivo models were included in the present review. Behavioral outcomes in the HD in vivo model showed that natural compounds significantly attenuated 3-nitropropionic acid (3-NP) induced memory loss and motor incoordination. The biochemical alteration has been markedly alleviated with reduced lipid peroxidation, increased endogenous enzymatic antioxidants, reduced acetylcholinesterase activity, and increased mitochondrial energy production. Interestingly, following treatment with certain natural products, 3-NP-induced damage in the striatum was ameliorated, as seen histologically. Overall, natural products afforded varying degrees of neuroprotection in preclinical studies of HD via antioxidant and anti-inflammatory properties, preservation of mitochondrial function, inhibition of apoptosis, and induction of autophagy.

Aptamer-functionalized pH-sensitive liposomes for a selective delivery of echinomycin into cancer cells

Echinomycin (quinomycin A) is a peptide antibiotic from the quinoxaline family, which has a DNA bifunctional intercalating activity and an inhibitor of hypoxia-inducible factor (HIF1α). Echinomycin was discovered in 1957 as a potent antitumor agent; however, it was not successful in clinical use due to its low water solubility and short half-life. To revitalize this potent drug, it is important to increase its aqueous solubility and bioavailability. In this study, echinomycin was loaded into PEGylated pH-sensitive liposomes (_PEGLip_pH) and functionalized with anti-nucleolin aptamer (Apt_NCL) for selective targeting and pH-responsive release of echinomycin into cancer cells. Echinomycin was complexed with γ-cyclodextrin (ECγCD) to enhance its water solubility and then encapsulated into pH-sensitive liposomes (_PEGLip_pH-ECγCD). Then, liposomes were functionalized with Apt_NCL (Apt_NCL-PEGLip_pH-ECγCD) and the successful functionalization was confirmed by dynamic light scattering (DLS) measurements and gel electrophoresis. Cellular uptake for Apt_NCL-PEGLip_pH was evaluated by flow cytometry analysis using MDA-MB-231, MCF7, A549 cancer cell lines with respect to the normal fibroblast cells. The results showed a higher uptake and selectivity for Apt_NCL-PEGLip_pH compared to _PEGLip_pH. The anti-proliferative effects of Apt_NCL-PEGLip_pH-ECγCD were more potent than _PEGLip_pH-ECγCD by 3.5, 4, and 5 folds for A549, MDA-MB-231, and MCF7, respectively. Selectivity indices (SI) for Apt_NCL-PEGLip_pH-ECγCD for the tumor cell lines compared to the normal cell line after 72 h were MDA-MB-231 (43.3), MCF7 (16.9), and A549 (8.5). Furthermore, SI after 3 h for the three cancer cell lines were 4.7, 2.5, 2.8, respectively.

Echinomycin was loaded into PEGylated pH-sensitive liposomes and functionalized with anti-nucleolin aptamer for selective targeting and pH-responsive release of echinomycin into cancer cells.

Cucurbituril-Oriented Nanoplatforms in Biomedical Applications

Cucucrbituril (CB) belongs to a family of macrocycles that are easily accessible. Their structural specificity provides excellent molecular recognition capabilities, with the ability to be readily chemically modified. Because of these properties, researchers have found CB to be a useful molecular carrier for delivering drug molecules and therapeutic biomolecules. Their significance lies in the fact that CB not only increases the solubility and stability of an encapsulated guest but also provides the possibility to achieve targeted delivery of the guest molecule. Therefore, the emergence of CB undoubtedly provides opportunities for the development of targeted drug delivery in an era where intelligent drugs have attracted considerable attention. It has also been found that CB can enhance fluorescent dyes, allowing the preparation of biosensors with enhanced sensitivity for use in clinical settings. In the present review, the acquisition, properties, and structural modifications of CB are first comprehensively described, and then the value of this macrocycle in applications within the medical field is discussed. In addition, we have also summarized patent applications of CB in this field over recent years, aiming to illustrate the current status of developments of this molecule. Finally, we discuss the challenges faced by CB in the medical field and future trends in its development.

Cyclodextrin-Based Functional Glyconanomaterials

Cyclodextrins (CDs) have long occupied a prominent position in most pharmaceutical laboratories as "off-the-shelve" tools to manipulate the pharmacokinetics of a broad range of active principles, due to their unique combination of biocompatibility and inclusion abilities. The development of precision chemical methods for their selective functionalization, in combination with "click" multiconjugation procedures, have further leveraged the nanoscaffold nature of these oligosaccharides, creating a direct link between the glyco and the nano worlds. CDs have greatly contributed to understand and exploit the interactions between multivalent glycodisplays and carbohydrate-binding proteins (lectins) and to improve the drug-loading and functional properties of nanomaterials through host-guest strategies. The whole range of capabilities can be enabled through self-assembly, template-assisted assembly or covalent connection of CD/glycan building blocks. This review discusses the advancements made in this field during the last decade and the amazing variety of functional glyconanomaterials empowered by the versatility of the CD component.

Transferrin-Conjugated pH-Responsive γ-Cyclodextrin Nanoparticles for Antitumoral Topotecan Delivery

In this study, we developed γ-cyclodextrin-based multifunctional nanoparticles (NPs) for tumor-targeted therapy. The NPs were self-assembled using a γ-cyclodextrin (γCD) coupled with phenylacetic acid (PA), 2,3-dimethylmaleic anhydride (DMA), poly(ethylene glycol) (PEG), and transferrin (Tf), termed γCDP-(DMA/PEG-Tf) NPs. These γCDP-(DMA/PEG-Tf) NPs are effective in entrapping topotecan (TPT, as a model antitumor drug) resulting from the ionic interaction between pH-responsive DMA and TPT or the host–guest interaction between γCDP and TPT. More importantly, the γCDP-(DMA/PEG-Tf) NPs can induce ionic repulsion at an endosomal pH (~6.0) resulting from the chemical detachment of DMA from γCDP, which is followed by extensive TPT release. We demonstrated that γCDP-(DMA/PEG-Tf) NPs led to a significant increase in cellular uptake and MDA-MB-231 tumor cell death. In vivo animal studies using an MDA-MB-231 tumor xenografted mice model supported the finding that γCDP-(DMA/PEG-Tf) NPs are effective carriers of TPT to Tf receptor-positive MDA-MB-231 tumor cells, promoting drug uptake into the tumors through the Tf ligand-mediated endocytic pathway and increasing their toxicity due to DMA-mediated cytosolic TPT delivery.

Potential ability of different types of cyclodextrins to modulate the interaction between bovine serum albumin and 1-hydroxypyrene

Hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) can bind with functional biomacromolecules and thus cause toxic effects in vivo. Four types of cyclodextrins (CDs) were selected to explore their potential ability to regulate the bindings between 1-hydroxypyrene (1-OHPyr) and bovine serum albumin (BSA) using multi-spectroscopic methods combined with molecular docking. The results showed that the four CDs caused varied modulating effects on the binding of BSA with 1-OHPyr, and the effects of γ-CD and (2-hydroxypropyl)-β-CD (HPCD) are the most significant. Specifically, γ-CD and HPCD could significantly reduce the binding affinity between 1-OHPyr and BSA, inhibit the micro-environmental changes of tryptophan residues, and slightly recover the helicity of BSA. The interactions and inclusion behavior of CDs with 1-OHPyr was the main reason why CDs could affect the binding of 1-OHPyr to BSA. The results indicated that γ-CD and HPCD might have potential application value in regulating the toxic effects of OH-PAHs.

In Vitro and In Vivo Comparison of Curcumin-Encapsulated Chitosan-Coated Poly(lactic-co-glycolic acid) Nanoparticles and Curcumin/Hydroxypropyl-β-Cyclodextrin Inclusion Complexes Administered Intranasally as Therapeutic Strategies for Alzheimer's Disease

Curcumin (CUR) has antioxidant and anti-inflammatory effects that are beneficial to Alzheimer's disease (AD). However, the poor solubility and high instability of CUR compromise its application greatly. In this study, CUR-encapsulated chitosan-coated poly (lactic-co-glycolic acid) nanoparticles (CUR-CS-PLGA-NPs) and hydroxypropyl-β-cyclodextrin-encapsulated CUR complexes (CUR/HP-β-CD inclusion complexes) were developed and compared through intranasal administration. In vitro studies indicated that CUR in CUR/HP-β-CD inclusion complexes was stable under physiological conditions over 72 h with 95.41 ± 0.01% remaining, which was higher than 49.66 ± 3.91% remaining in CUR-CS-PLGA-NPs. Meanwhile, CUR/HP-β-CD inclusion complexes showed a higher cellular uptake level of CUR than CUR-CS-PLGA-NPs in SH-SY5Y cells. Both formulations could reduce CUR's cellular cytotoxicity and showed a comparable antioxidant effect. Both formulations displayed the anti-inflammatory effect at 20 μM CUR in BV-2 cells, which decreased TNF-α and IL-6 levels to approximately 70 and 40%, respectively, when compared to the positive control, respectively. In vivo pharmacokinetic studies indicated that after intranasal administration, the AUC values of CUR in the plasma and brain of the CUR/HP-β-CD inclusion complex group were 2.57-fold and 1.12-fold higher than those in the CUR-CS-PLGA-NP group at the same dose of 2 mg/kg, respectively. In conclusion, CUR/HP-β-CD inclusion complexes displayed better properties than CUR-CS-PLGA-NPs as a carrier for intranasal delivery of CUR for application in AD.

Cyclodextrins in Parenteral Formulations

Most drugs have very limited solubility in water and some can be extremely difficult to formulate as parenteral solutions where the dose should preferably be dissolved in couple of ml of aqueous media without use of organic solvents and surface active agents, or application of somewhat extreme techniques such as prodrug formation. Thus, pharmaceutical formulators are constantly looking for new, biologically acceptable, and low-cost armamentarium for parenteral formulation development. Cyclodextrins (CDs) are enabling pharmaceutical excipients that can temporarily camouflage undesirable physiochemical drug properties such as low aqueous solubility through formation of drug/CD inclusion complexes. CDs are cyclic oligosaccharides that have similar physiological and biological properties like linear saccharides of comparable molecular weight. Due to their very favorable toxicological and pharmacokinetic profiles their usage in parenteral drug formulations is frequently preferred over other solubilizing techniques. Here the physiochemical and biological properties of CDs are reviewed as well as their pharmacokinetics after intravenous administration. Their regulatory status is briefly reviewed and their tendency to self-assemble to form clusters or aggregates discussed. Finally, some examples are given of how CDs are applied in aqueous parenteral formulations, how their solubilizing effect has been enhanced and how their target concentration is determined.

Cyclodextrin-grafted nanoparticles as food preservative carriers

Photocatalytic properties of titanium dioxide nanoparticles (TiO₂ NPs) have encouraged their use as fillers in polymer-based nanocomposites for application in food packaging. The surface modification of TiO₂ NPs with cyclodextrins (CDs) can improve their functionality in a large extent. With this purpose, sorbic acid (SA) and benzoic acid (BA), commonly used as antifungal and antibacterial food preservatives, respectively, have been encapsulated in CD-grafted NPs. Inclusion complex formation of SA and BA with α and βCDs in water has been assessed first by means of ¹H NMR and UV-Vis spectroscopy to determine the affinity of the preservatives for the macrocycles and the stoichiometry of the complexes. The association constants of both preservatives were found to be lower for βCD, however, the loading efficiency in βCD-grafted NPs was higher than that exhibited by αCD-NPs. Release kinetics from the CD-grafted NPs have been carried out. In the case of SA, the αCD-grafted NPs showed a prolonged and sustained release profile, suggesting its application as microbial growth inhibition system if incorporated into packaging materials.

Enhanced-fluorescent imaging and targeted therapy of liver cancer using highly luminescent carbon dots-conjugated foliate

Carbon dots (CDs) have shown great potential in drug delivery and biological imaging applications. In this work, a doxorubicin (DOX) delivery carrier and imaging probe for liver cancer-targeted therapy was designed based on CDs with high fluorescence quantum yield (97%), aiming to enhance the antitumor activity and imaging efficiency. Folic acid (FA), which showed high expression in hepatoma cells, was used as targeting components to modify CDs (FA-CDs), and then FA-CDs-DOX was obtained by loading DOX. Results show that CDs and FA-CDs have good biocompatibility, and the DOX release from FA-CDs-DOX is targeted and selective. Confocal microscope demonstrates that FA-CDs-DOX has excellent ability of fluorescence imaging in liver cancer cells. The imaging in vivo shows the fluorescence intensity of FA-CDs-DOX is strong enough to penetrate tumor tissue and skin, further verifying its enhanced-fluorescent imaging effects. Tumor inhibition in vivo indicates that the targeting ability of FA-CDs-DOX is significantly higher than that of free DOX, showing obvious better therapeutic effect. To sum up, the targeted and fluorescent drug delivery system based on CDs with high fluorescence quantum yield show an excellent imaging in vivo and tumor inhibition effect, which provide a novel strategy for promoting the potential clinical application of CDs in liver cancer treatment.

Resveratrol Delivery from Implanted Cyclodextrin Polymers Provides Sustained Antioxidant Effect on Implanted Neural Probes

Intracortical microelectrodes are valuable tools used to study and treat neurological diseases. Due in large part to the oxidative stress and inflammatory response occurring after electrode implantation, the signal quality of these electrodes decreases over time. To alleviate this response, resveratrol, a natural antioxidant which elicits neuroprotective effects through reduction of oxidative stress, was utilized. This work compares traditional systemic delivery of resveratrol to the novel cyclodextrin polymer (pCD) local delivery approach presented herein, both in vitro and in vivo. The pCD displayed an extended resveratrol release for 100 days, as well as 60 days of free radical scavenging activity in vitro. In vivo results indicated that our pCD delivery system successfully delivered resveratrol to the brain with a sustained release for the entire short-duration study (up to 7 days). Interestingly, significantly greater concentrations of resveratrol metabolites were found at the intracortical probe implantation site compared to the systemic administration of resveratrol. Together, our pilot results provide support for the possibility of improving the delivery of resveratrol in an attempt to stabilize long-term neural interfacing applications.

Carbon dots-inspired fluorescent cyclodextrins: competitive supramolecular "off-on" (bio)sensors

Chromophore-appended cyclodextrins combine the supramolecular loading capabilities of cyclodextrins (CDs) with the optical properties of the affixed chromophores. Among fluorescent materials, carbon dots (CNDs) are attractive and the feasibility of CND-appended CDs as sensors has been demonstrated by different authors. However, CNDs are intrinsically heterogeneous materials and their ulterior functionalization yields hybrid composites that are not well defined in terms of structure and composition. Inspired by the fluorescence properties of 5-oxo-1,2,3,5-tetrahydroimidazo[1,2-a]pyridine-7-carboxylic acid (IPCA), the most paradigmatic of the molecular fluorophores detected in CNDs, herein we report two highly efficient synthetic chemical strategies for the preparation of IPCA-appended CDs that behave as CND-based CD "turn off-on" biosensors suitable for the analysis of cholesterol and β-galactosidase activity. We have deconstructed the CND-CD systems to demonstrate that (i) the role of CNDs is limited to acting as a support for the molecular fluorophores produced during their synthesis and (ii) the molecular fluorophores suffice for the determination of the enzymatic activity based on the quenching by p-nitrophenol as a sacrificial quencher.

Citric acid-crosslinked β-cyclodextrin supported zinc peroxide as a biocompatible H2O2 scavenger

The aim of the present study was to evaluate the H₂O₂ scavenging activity of the ZnO₂/β-CD as a biocompatible composite. Zinc peroxide was prepared via sonochemical approach. To synthesize a green composite, β-cyclodextrin was modified by citric acid (CA) and reacted with ZnO₂ under ultrasonic irradiation. The prepared samples were characterized using XRD, SEM, TGA and FTIR analytical techniques. XRD analysis exhibited a typical pattern of ZnO₂ and demonstrated the presence of citric acid and β-cyclodextrin in composite. The results of the catalytic assay showed that the ZnO₂/CA-βCD composite displayed stronger capability to decompose H₂O₂ in comparison to ZnO₂ particles (about seven times). It was attributed to increased adsorption capacity and solubility of composite due to the presence of citric acid and β-cyclodextrin. MTT assay studies confirmed the non-cytotoxic nature of ZnO₂ particles and ZnO₂/CA-βCD composite.

Cyclodextrin Based Nanoparticles for Drug Delivery and Theranostics

Colloidal nanoparticulate technology has been described in the literature as a versatile drug delivery system. But it possesses some inherent lacunae in their formulation. Cyclodextrins (CDs) have been extensively reported for the solubility enhancement of poorly water-soluble drugs. The CDs can cause intervention in aspects related to nanoparticles (NPs) that include improving drug loading in nano-system, improving stability, site-specific/targeted drug delivery, improving solubility profile and absorption of the drug in nanosystem with consequent improvement in bioavailability, with the possibility of controlled release, safety and efficacy. They find application in for simultaneous diagnosis and therapeutics for better treatment procedures. The current communication is focused on the application of CDs to overcome troubles in nanoparticulate formulation and enhancement of their performance. It also envisages the theranostic aspects of CDs.

A stepwise optimization strategy to formulate in situ gelling formulations comprising fluconazole-hydroxypropyl-beta-cyclodextrin complex loaded niosomal vesicles and Eudragit nanoparticles for enhanced antifungal activity and prolonged ocular delivery

Fungal keratitis and endopthalmitis are serious eye diseases. Fluconazole (FL) is indicated for their treatment, but suffers from poor topical ocular availability. This study was intended to improve and prolong its ocular availability. FL niosomal vesicles were prepared using span 60. Also, polymeric nanoparticles were prepared using cationic Eudragit RS100 and Eudragit RL100. The investigated particles had adequate entrapment efficiency (EE%), nanoscale particle size and high zeta potential. Subsequently, formulations were optimized using full factorial design. FL-HP-β-CD complex was encapsulated in selected Eudragit nanoprticles (FL-CD-ERS1) and niosmal vesicles. The niosomes were further coated with cationic and bioadhesive chitosan (FL-CD-Nios-ch). EE% for FL-CD-ERS1 and FL-CD-Nios-ch formulations were 76.4% and 61.7%; particle sizes were 151.1 and 392 nm; also, they exhibited satisfactory zeta potential +40.1 and +28.5 mV. In situ gels were prepared by poloxamer P407, HPMC and chitosan and evaluated for gelling capacity, rheological behavior and gelling temperature. To increase the precorneal residence time, free drug and selected nano-formulations were incorporated in the selected in situ gel. Release study revealed sustained release within 24 h. Permeation through excised rabbits corneas demonstrated enhanced drug flux and large AUC_0-6h in comparison to plain drug. Corneal permeation of selected formulations labeled with Rhodamine B was visualized by Confocal laser microscopy. Histopathological study and in vivo tolerance test evidenced safety. In vivo susceptibility test using Candida albicans depicted enhanced growth inhibition and sustained effect. In this study the adopted stepwise optimization strategy combined cylodextrin complexation, drug nano-encapsulation and loading within thermosenstive in situ gel. Finally, the developed innovated formulations displayed boosted corneal permeation, enhanced antifungal activity and prolonged action.

Cyclodextrin polymer improves atherosclerosis therapy and reduces ototoxicity

Recently, cyclodextrin (CD) has shown the potential for effective treatment of atherosclerotic plaques in mice by solubilizing plaque cholesterol. While promising as a new therapy for atherosclerosis, poor pharmacokinetics and ototoxicity of CD pose a therapeutic challenge. Thus far, however, there has been no attempts to overcome such limitations. Here, we showed that cyclodextrin polymer (CDP) with a diameter of ~ 10 nm exhibits outstanding pharmacokinetics and plaque targeting efficacy compared to a monomeric CD. Furthermore, we found out that CDP does not induce plasma membrane disruption as opposed to CD, which eliminated cytotoxicity and hemolytic activity of CD. In a mouse model of atherosclerosis, subcutaneous injections of beta-cyclodextrin polymer (βCDP) significantly inhibited plaque growth compared to monomeric hydroxypropyl-beta-cyclodextrin (HPβCD) at the same dose (1 g/kg). More importantly, βCDP did not induce significant ototoxicity at a high-dose (8 g/kg) where HPβCD reduced the outer hair cell content by 36%. These findings suggest that the polymerization of CD can overcome major limitations of CD therapy for treatment of atherosclerosis.

Fibrin gels entrapment of a doxorubicin-containing targeted polycyclodextrin: Evaluation of in vivo antitumor activity in orthotopic models of human neuroblastoma

In vivo local antitumor activity of fibrin gels (FBGs) loaded with the poly-cyclodextrin oCD-NH₂/Dox, compared to free Dox, was evaluated in two mouse orthotopic neuroblastoma (NB) models, after positioning of the releasing devices in the visceral space. FBGs were prepared at the fibrinogen (FG) concentrations of 22 and 40 mg/ml clotted in the presence of 0.81 mM/mg FG Ca²⁺ and 1.32 U/mg FG thrombin. Our results indicate that FBGs loaded with oCD-NH₂/Dox and applied as neoadjuvant loco-regional treatment, show an antitumor activity significantly greater than that displayed by the same FBGs loaded with identical dose of Dox or after free Dox administered intra venous (iv). In particular, FBGs prepared at 40 mg/ml showed a slightly lower antitumor activity, although after their positioning we observed a significant initial reduction of tumor burden lasting for several days after gel implantation. FBGs at 22 mg/ml loaded with oCD-NH₂/Dox and applied after tumor removal (adjuvant treatment model) showed a significantly better antitumor activity than the iv administration of free Dox, with 90% tumor regrowth reduction compared to untreated controls. In all cases the weight loss post-treatment was limited after gel application, although in the adjuvant treatment the loss of body weight lasted longer than in the other treatment modality. In accordance with our recent published data on the low local toxic effects of FBGs, the present findings also underline an increase of the therapeutic index of Dox when locally administered through FBGs loaded with the oCD-NH₂/Dox complex.

Safe nanotechnologies for increasing the effectiveness of environmentally friendly natural agrochemicals

Natural compounds and living organisms continue to play a limited role in crop protection, and few of them have reached the market, despite their attractiveness and the efforts made in research. Very often these products have negative characteristics compared to synthetic compounds, e.g., higher costs of production, lower effectiveness, lack of persistence, and inability to reach and penetrate the target plant. Conversely, nanotechnologies are having an enormous impact on all human activities, including agriculture, even if the production of some nanomaterials is not environmentally friendly or could have adverse effects on agriculture and the environment. Thus, certain nanomaterials could facilitate the development of formulated natural pesticides, making them more effective and more environmentally friendly. Nanoformulations can improve efficacy, reduce effective doses, and increase shelf-life and persistence. Such controlled-release products can improve delivery to the target pest. This review considers certain available nanomaterials and nanotechnologies for use in agriculture, discussing their properties and the feasibility of their use in sustainable crop protection, in particular, in improving the effectiveness of natural bio-based agrochemicals. © 2019 Society of Chemical Industry.

Preparation, Characterization, and Properties of Inclusion Complexes of Balofloxacin with Cyclodextrins

The study mainly aimed to improve the aqueous solubility of Balofloxacin (BLFX) by preparing the inclusion complexes (ICs) of BLFX with cyclodextrins (CDs). In this study, ICs in solid state were obtained by using beta-CD (β-CD), 2-hydroxypropyl-β-CD (HP-β-CD), 2, 6-dimethyl-β-CD (DM-β-CD) through a freeze-drying technique. The formation of ICs was confirmed through Fourier-transform infrared spectroscopy, differential scanning calorimetry, powder X-ray diffraction, nuclear magnetic resonance, and scanning electron microscopy. Results demonstrated that the water solubility and dissolution rates of three ICs were distinctly improved than that of parent BLFX. Bacteriostatic experiment manifested that the antibacterial effect of BLFX was not inhibited after encapsulation in CDs. The damage of BLFX to kidney and liver cells was reduced. Consequently, successful preparation of the ICs of BLFX with CDs provided possibility for devising new dosage form of BLFX, which held great promise for further applications in clinical fields.

Characteristics, Biological Properties and Analytical Methods of Trans-Resveratrol: A Review

Trans-resveratrol (TR) is the biological active isomer of resveratrol and the one responsible for therapeutic effects; both molecules are non-flavonoid phenolics of the stilbenes class found mainly in berries and red grapes. TR biological properties lie in modulation of various enzymatic classes. It is a promising candidate to novel drugs due its applications in pharmaceutical and cosmetic industries, such as anticarcinogenic, antidiabetic, antiacne, antioxidant, anti-inflammatory, neuroprotective, and photoprotector agent. It has effects on bone metabolism, gastrointestinal tract, eyes, kidneys, and in obesity treatment as well. Nevertheless, its low solubility in water and other polar solvents may be a hindrance to its therapeutic effects. Various strategies been developed to overcome these issues, such as the drug delivery systems. The present study performed a research about methods to identify TR and RESV in several samples (raw materials, wines, food supplements, drug delivery systems, and blood plasma). Most of the studies tend to analyze TR and RESV by high performance liquid chromatography (HPLC) coupled with different detectors, even so, there are reports of the use of capillary electrophoresis, electron spin resonance, gas chromatography, near-infrared luminescence, UV-Vis spectrophotometer, and vibrational spectrophotometry, for this purpose. Thus, the review evaluates the biological activity of TR and demonstrates the currently used analytical methods for its quantification in different matrices.

Paclitaxel-Trastuzumab Mixed Nanovehicle to Target HER2-Overexpressing Tumors

Paclitaxel is one of the most widely used chemotherapeutic agents thanks to its effectiveness and broad spectrum of antitumor activity. However, it has a very poor aqueous solubility and a limited specificity. To solve these handicaps, a novel paclitaxel-trastuzumab targeted transport nanosystem has been developed and characterized in this work to specifically treat cancer cells that overexpress the human epidermal growth factor receptor-2 (HER2). Methods: Alginate and piperazine nanoparticles were synthetized and conjugated with paclitaxel:β-cyclodextrins complexes and trastuzumab. Conjugated nanoparticles (300 nm) were characterized and their internalization in HER2-overexpressing tumor cells was analyzed by immunofluorescence. Its specific antitumor activity was studied in vitro using human cell lines with different levels of HER2-expression. Results: In comparison with free paclitaxel:β-cyclodextrins complexes, the developed conjugated nanovehicle presented specificity for the treatment of HER2-overpressing cells, in which it was internalized by endocytosis. Conclusions: It seems that potentially avoiding the conventional adverse effects of paclitaxel treatment could be possible with the use of the proposed mixed nanovehicle, which improves its bioavailability and targets HER2-positive cancer cells.

Synthesis and characterization of a new cyclodextrin derivative with improved properties to design oral dosage forms

This work aimed to synthesize a novel β-cyclodextrin derivative, itaconyl-β-cyclodextrin to evaluate whether albendazole inclusion complexes with the new β-cyclodextrin derivative-improved albendazole dissolution efficiency and its anthelminthic activity. The new derivative was thoroughly evaluated and characterized, and an average degree of substitution of 1.4 per cyclodextrin molecule was observed. Albendazole:itaconyl-β-cyclodextrin complexes were prepared by spray drying procedures and investigated using phase solubility diagrams, dissolution efficiency, X-ray diffraction, differential scanning calorimetry, Fourier transform infrared, scanning electronic microscopy, mass spectrometry, and nuclear magnetic resonance spectroscopy. Phase solubility diagrams and mass spectrometry studies showed that the inclusion complex was formed in an equimolar ratio. Stability constant values were 602 M^-1 in water, and 149 M^-1 in HCl 0.1 N. Nuclear magnetic resonance experiments of the inclusion complex showed correlation signals between the aromatic and propyl protons of albendazole and the itaconyl-β-cyclodextrin inner protons. The studies indicated solid structure changes of albendazole included in itaconyl-β-cyclodextrin. The maximum drug release was reached at 15 min, and the inclusion complex solubility was 88-fold higher than that of the pure drug. The in vitro anthelmintic activity assay showed that the complex was significantly more effective than pure albendazole.

Methyl-β-cyclodextrin, an actin depolymerizer augments the antiproliferative potential of microtubule-targeting agents

Methyl-β-cyclodextrin (MCD), an established pharmacological excipient, depolymerizes the actin cytoskeleton. In this work, we investigated the effect of MCD-mediated actin depolymerization on various cellular phenotypes including traction force, cell stiffness, focal adhesions, and intracellular drug accumulation. In addition to a reduction in the contractile cellular traction, MCD acutely inhibits the maturation of focal adhesions. Alteration of contractile forces and focal adhesions affects the trypsin-mediated detachment kinetics of cells. Moreover, MCD-mediated actin depolymerization increases the intracellular accumulation of microtubule-targeting agents (MTAs) by ~50% with respect to the untreated cells. As MCD treatment enhances the intracellular concentration of drugs, we hypothesized that the MCD-sensitized cancer cells could be effectively killed by low doses of MTAs. Our results in cervical, breast, hepatocellular, prostate cancer and multidrug-resistant breast cancer cells confirmed the above hypothesis. Further, the combined use of MCD and MTAs synergistically inhibits the proliferation of tumor cells. These results indicate the potential use of MCD in combination with MTAs for cancer chemotherapy and suggest that targeting both actin and microtubules simultaneously may be useful for cancer therapy. Importantly, the results provide significant insight into the crosstalk between actin and microtubules in regulating the traction force and dynamics of cell deadhesion.

Modification of Chitosan for the Generation of Functional Derivatives

Today, chitosan (CS) is probably considered as a biofunctional polysaccharide with the most notable growth and potential for applications in various fields. The progress in chitin chemistry and the need to replace additives and non-natural polymers with functional natural-based polymers have opened many new opportunities for CS and its derivatives. Thanks to the specific reactive groups of CS and easy chemical modifications, a wide range of physico-chemical and biological properties can be obtained from this ubiquitous polysaccharide that is composed of β-(1,4)-2-acetamido-2-deoxy-d-glucose repeating units. This review is presented to share insights into multiple native/modified CSs and chitooligosaccharides (COS) associated with their functional properties. An overview will be given on bioadhesive applications, antimicrobial activities, adsorption, and chelation in the wine industry, as well as developments in medical fields or biodegradability.

Use of affinity allows anti-inflammatory and anti-microbial dual release that matches suture wound resolution

Surgical sutures are vulnerable to bacterial infections and biofilm formation. At the suture site, pain and undesirable, excess inflammation are additionally detrimental to wound healing. The development of a polymerized cyclodextrin (pCD) coated surgical suture introduces the capability to locally deliver both anti-inflammatory and anti-microbial drugs throughout the phases of acute and chronic healing. Local delivery allows for the improvement of wound healing while reducing related systemic side effects and drug resistance. Through testing, it has been shown that the fabrication of our pCD coating minimally affects the suture's mechanical properties. In vitro studies show measurable and consistent drug delivery for nearly 5 weeks. The therapeutic level of this delivery is sufficient to show inhibition of bacterial growth for 4 weeks, and free-radical scavenging (an in vitro anti-inflammatory activity approximation) for 2 weeks. With this pCD coating technique, we maintain clinical performance standards while also introducing a long-term dual delivery system relevant to the wound healing timeframe. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2019.

1,4-Dihydropyridine Antihypertensive Drugs: Recent Advances in Photostabilization Strategies

The 1,4-dihydropyridine (DHP) drugs are nowadays the most used drugs in the treatment of hypertension. However, all the structures in this series present a significant sensitivity to light, leading to the complete loss of pharmacological activity. This degradation is particularly evident in aqueous solution, so much so that almost all DHP drugs on the market are formulated in solid preparations, especially tablets. The first and main process of photodegradation consists in the aromatization of the dihydropyridine ring, after which secondary processes can take place on the various substituents. A potential danger can result from the formation of single oxygen and superoxide species that can in turn trigger phototoxic reactions. Several strategies for the photostabilisation of DHP drugs have been proposed in recent years, in particular with the aim to formulate these drugs in liquid preparations, as well as to limit any toxicity problems related to light degradation. This review summarizes and describes the main aspects of the studies conducted in recent years to obtain photostable formulations of DHP drugs.

Nepafenac-Loaded Cyclodextrin/Polymer Nanoaggregates: A New Approach to Eye Drop Formulation

The topical administration route is commonly used for targeting therapeutics to the eye; however, improving the bioavailability of drugs applied directly to the eye remains a challenge. Different strategies have been studied to address this challenge. One of them is the use of aggregates that are formed easily by self-assembly of cyclodextrin (CD)/drug complexes in aqueous solution. The aim of this study was to design a new eye drop formulation based on aggregates formed between CD/drug complexes. For this purpose, the physicochemical properties of the aggregates associated with six CDs and selected water-soluble polymers were analysed. Complex formation was studied using differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR) and ¹H nuclear magnetic resonance spectroscopy (¹H-NMR). Results showed that HPβCD performed best in terms of solubilization, while γCD performed best in terms of enhancing nanoaggregate formation. Formation of inclusion complexes was confirmed by DSC, FT-IR and ¹H-NMR studies. A mixture of 15% (w/v) γCD and 8% (w/v) HPβCD was selected for formulation studies. It was concluded that formulations with aggregate sizes less than 1 µm and viscosity around 10–19 centipoises can be easily prepared using a mixture of CDs. Formulations containing polymeric drug/CD nanoaggregates represent an interesting strategy for enhanced topical delivery of nepafenac.

Novel Findings about Double-Loaded Curcumin-in-HPβcyclodextrin-in Liposomes: Effects on the Lipid Bilayer and Drug Release

In this study, the encapsulation of curcumin (Cur) in “drug-in-cyclodextrin-in-liposomes (DCL)” by following the double-loading technique (DL) was proposed, giving rise to DCL–DL. The aim was to analyze the effect of cyclodextrin (CD) on the physicochemical, stability, and drug-release properties of liposomes. After selecting didodecyldimethylammonium bromide (DDAB) as the cationic lipid, DCL–DL was formulated by adding 2-hydroxypropyl-α/β/γ-CD (HPβCD)–Cur complexes into the aqueous phase. A competitive effect of cholesterol (Cho) for the CD cavity was found, so cholesteryl hemisuccinate (Chems) was used. The optimal composition of the DCL–DL bilayer was obtained by applying Taguchi methodology and regression analysis. Vesicles showed a lower drug encapsulation efficiency compared to conventional liposomes (CL) and CL containing HPβCD in the aqueous phase. However, the presence of HPβCD significantly increased vesicle deformability and Cur antioxidant activity over time. In addition, drug release profiles showed a sustained release after an initial burst effect, fitting to the Korsmeyer-Peppas kinetic model. Moreover, a direct correlation between the area under the curve (AUC) of dissolution profiles and flexibility of liposomes was obtained. It can be concluded that these “drug-in-cyclodextrin-in-deformable” liposomes in the presence of HPβCD may be a promising carrier for increasing the entrapment efficiency and stability of Cur without compromising the integrity of the liposome bilayer.

Methyl-β-Cyclodextrin Impairs the Phosphorylation of the β₂ Subunit of L-Type Calcium Channels and Cytosolic Calcium Homeostasis in Mature Cerebellar Granule Neurons

The activation of L-type calcium channels (LTCCs) prevents cerebellar granule neurons (CGNs) from entering low-K⁺-induced apoptosis. In previous works, we showed that LTCCs are largely associated with caveolin-1-rich lipid rafts in the CGN plasma membrane. In this work, we show that protein kinase A (PKA) and calmodulin-dependent protein kinase II (CaMK-II) are associated with caveolin-1-rich lipid rafts of mature CGNs, and we further show that treatment with the cholesterol-trapping and lipid raft-disrupting agent methyl-β-cyclodextrin decreases the phosphorylation level of the LTCC β₂ subunit and the steady-state calcium concentration in neuronal somas ([Ca²⁺]_i) to values close to those measured in 5 mM KCl proapoptotic conditions. These effects correlate with the effects produced by a short (15 min) treatment of CGNs with H-89 and KN-93—inhibitors of PKA and CaMK-II, respectively—in 25 mM KCl medium. Moreover, only a 15 min incubation of CGNs with H-89 produces about a 90% inhibition of the calcium entry that would normally occur through LTCCs to increase [Ca²⁺]_i upon raising the extracellular K⁺ from 5 to 25 mM, i.e., from proapoptotic to survival conditions. In conclusion, the results of this work suggest that caveolin-1-rich lipid rafts play a major role in the control of the PKA- and CaMK-II-induced phosphorylation level of the LTCC β₂ subunit, thus preventing CGNs from entering apoptosis.