Supramolecular hydrogels of β-cyclodextrin linked to calcium homopoly-l-guluronate for release of coumarins with trypanocidal activity

In Vitro Evaluation of New 5-Nitroindazolin-3-one Derivatives as Promising Agents against Trypanosoma cruzi

Chagas disease is a prevalent health problem in Latin America which has received insufficient attention worldwide. Current treatments for this disease, benznidazole and nifurtimox, have limited efficacy and may cause side effects. A recent study proposed investigating a wide range of nitroindazole and indazolone derivatives as feasible treatments. Therefore, it is proposed that adding a nitro group at the 5-position of the indazole and indazolone structure could enhance trypanocidal activity by inducing oxidative stress through activation of the nitro group by NTRs (nitroreductases). The study results indicate that the nitro group advances free radical production, as confirmed by several analyses. Compound 5a (5-nitro-2-picolyl-indazolin-3-one) shows the most favorable trypanocidal activity (1.1 ± 0.3 µM in epimastigotes and 5.4 ± 1.0 µM in trypomastigotes), with a selectivity index superior to nifurtimox. Analysis of the mechanism of action indicated that the nitro group at the 5-position of the indazole ring induces the generation of reactive oxygen species (ROS), which causes apoptosis in the parasites. Computational docking studies reveal how the compounds interact with critical residues of the NTR and FMNH2 (flavin mononucleotide reduced) in the binding site, which is also present in active ligands. The lipophilicity of the studied series was shown to influence their activity, and the nitro group was found to play a crucial role in generating free radicals. Further investigations are needed of derivatives with comparable lipophilic characteristics and the location of the nitro group in different positions of the base structure.

One-Step Physical and Chemical Dual-Reinforcement with Hydrophobic Drug Delivery in Gelatin Hydrogels for Antibacterial Wound Healing

Gelatin-based bioadhesives, especially methacrylated gelatin (GelMA), have emerged as superior alternatives to sutureless wound closure. Nowadays, their mechanical improvement and therapeutic delivery, particularly for hydrophobic antibiotics, have received ever-increasing interest. Herein, a reinforced gelatin-based hydrogel with a hydrophobic drug delivery property for skin wound treatment was reported. First, photosensitive monomers of N'-(2-nitrobenzyl)-N-acryloyl glycinamide (NBNAGA) were grafted onto GelMA via Michael addition, namely, GelMA-NBNAGA. Second, gelation of the GelMA-NBNAGA solution was accomplished in a few seconds under one step of ultraviolet (UV) light irradiation. Multiple effects were realized simultaneously, including chemical cross-linking initiated by lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP), physical cross-linking of uncaged dual hydrogen bonding, and hydrophobic drug release along with o-NB group disintegration. The mechanical properties of the dual-reinforcement hydrogels were verified to be superior to those only with a chemical or physical single-cross-linked network. The hydrophobic anticancer doxorubicin (DOX) and antibiotic rifampicin (Rif) were successfully charged into the hydrogels, separately. The in vitro antimicrobial tests confirmed the antibacterial activity of the hydrogels against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. The in vivo wound-healing assessment in mice further assured their drug release and efficacy. Therefore, this NBNAGA-modified GelMA hydrogel has potential as a material in skin wound dressing with a hydrophobic antibiotic on-demand delivery.

Silica modified copper-based alginate/chitosan hybrid hydrogel to control soil fumigant release, reduce emission and enhance bioactivity

Soil fumigant has been extensively used for excellent efficacy on soil-borne diseases. However, rapid emission and insufficient effective duration typically limit its application. In this study, hybrid silica/polysaccharide hydrogel was proposed (SIL/Cu/DMDS) by emulsion-gelation method to encapsulate dimethyl disulfide (DMDS). The orthogonal study was used to optimize the preparation parameters for LC and EE of SIL/Cu/DMDS, which was 10.39 % and 71.05 %, respectively. Compared with silica, the time for 90 % of the total emissions was extended by 4.36 times. The hydrogel possessed a longer persistent duration and the degradation half-life of DMDS was 3.47 times greater than that of silica alone. Moreover, the electrostatic interaction between abundant groups of polysaccharide hydrogel bestowed DMDS with pH-triggered release behavior. Additionally, SIL/Cu/DMDS had excellent water holding and water retention capacity. The bioactivity of the hydrogel was 58.1 % higher than that of DMDS TC due to the strong synergistic effect between DMDS and the carriers (chitosan and Cu²⁺), and showed obvious biosafety to cucumber seeds. This study seeks to provide a potential approach to develop hybrid polysaccharide hydrogel to control soil fumigants release, reduce emission and enhance bioactivity in plant protection.

Assembled Bisphenol A with cyclic oligosaccharide as the controlled release complex to reduce risky effects

Herein, in order to improve the bioavailability of a non-biodegradable pollutant, inclusion complexation procedures had been used to develop better formulations of this pollutant, Bisphenol A (BPA). In our research, an inclusion complex (IC) of β-cyclodextrin (β-CD) with BPA was formed to investigate the effect of β-CD on the water solubility, anti-oxidant, anti-bacterial activity, toxicity, and thermal stability of BPA. UV-Vis and other spectrometric methods such as NMR, FTIR, and XRD indicated the molecular mechanism of interactions between β-CD and BPA, which was further hypothesized using molecular modeling to confirm preliminary results. Studies of TGA and DSC demonstrated that encapsulation boosted the thermal stability of BPA. This research also makes predictions about BPA's release behavior when CT-DNA is present. In vitro testing of the IC's antibacterial activities showed that it outperformed pure BPA. The in silico study was found to have a considerable decrease in toxicity level for IC compared to pure BPA. Therefore, β-CD-encapsulated BPA can lessen toxicity by raising antioxidant levels. Additionally, as its antibacterial activity increases, it may be employed therapeutically. Thus, this discovery of creating BPA formulations with controlled release and/or protective properties allows for a more logical application of BPA by reducing its hazardous effects through boosting its efficacy.

In Vitro and In Vivo Evaluation of Hydroxypropyl-β-cyclodextrin-grafted-poly(acrylic acid)/poly(vinyl pyrrolidone) Semi-Interpenetrating Matrices of Dexamethasone Sodium Phosphate

In this paper, we fabricated semi-interpenetrating polymeric network (semi-IPN) of hydroxypropyl-β-cyclodextrin-grafted-poly(acrylic acid)/poly(vinyl pyrrolidone) (HP-β-CD-g-poly(AA)/PVP) by the free radical polymerization technique, intended for colon specific release of dexamethasone sodium phosphate (DSP). Different proportions of polyvinyl pyrrolidone (PVP), acrylic acid (AA), and hydroxypropyl-beta-cyclodextrin (HP-β-CD) were reacted along with ammonium persulphate (APS) as initiator and methylene-bis-acrylamide (MBA) as crosslinker to develop a hydrogel system with optimum swelling at distal intestinal pH. Initially, all formulations were screened for swelling behavior and AP-8 was chosen as optimum formulation. This formulation was capable of releasing a small amount of drug at acidic pH (1.2), while a maximum amount of drug was released at colonic pH (7.4) by the non-Fickian diffusion mechanism. Fourier transformed infrared spectroscopy (FTIR) revealed successful grafting of components and development of semi-IPN structure without any interaction with DSP. Thermogravimetric analysis (TGA) confirmed the thermal stability of developed semi-IPN. X-ray diffraction (XRD) revealed reduction in crystallinity of DSP upon loading in the hydrogel. The scanning electron microscopic (SEM) images revealed a rough and porous hydrogel surface. The toxicological evaluation of semi-IPN hydrogels confirmed their bio-safety and hemocompatibility. Therefore, the prepared hydrogels were pH sensitive, biocompatible, showed good swelling, mechanical properties, and were efficient in releasing the drug in the colonic environment. Therefore, AP-8 can be deemed as a potential carrier for targeted delivery of DSP to treat inflammatory bowel diseases.

Exploring inclusion complex of an anti-cancer drug (6-MP) with β-cyclodextrin and its binding with CT-DNA for innovative applications in anti-bacterial activity and photostability optimized by computational study

The co-evaporation approach was used to examine the host-guest interaction and to explore the cytotoxic and antibacterial properties of an important anti-cancer medication, 6-mercaptopurine monohydrate (6-MP) with β-cyclodextrin (β-CD). The UV-Vis investigation confirmed the inclusion complex's (IC) 1 : 1 stoichiometry and was also utilized to oversee the viability of this inclusion process. FTIR, NMR, and XRD, among other spectrometric techniques, revealed the mechanism of molecular interactions between β-CD and 6-MP which was further hypothesized by DFT to verify tentative outcomes. TGA and DSC studies revealed that 6-MP's thermal stability increased after encapsulation. Because of the protection of drug 6-MP by β-CD, the formed IC was found to have higher photostability. This work also predicts the release behavior of 6-MP in the presence of CT-DNA without any chemical changes. An evaluation of the complex's antibacterial activity in vitro revealed that it was more effective than pure 6-MP. The in vitro cytotoxic activity against the human kidney cancer cell line (ACHN) was also found to be significant for the IC (IC50 = 4.18 μM) compared to that of pure 6-MP (IC50 = 5.49 μM). These findings suggest that 6-MP incorporation via β-CD may result in 6-MP stability and effective presentation of its solubility, cytotoxic and antibacterial properties.

Alginate/gelatin-based hybrid hydrogels with function of injecting and encapsulating cells in situ

Multi-network hydrogels with high strength and toughness have attracted increasing attention. Herein, a hybrid hydrogel consisting of alginate, gelatin, and polyacrylamide was constructed with the combination of advantages of natural and synthetic polymers. Alginate grafted with host-guest complex of βCD/Ad-AAm was first prepared, namely Alg-βCD/Ad-AAm, then further crosslink with gelatin methacryloyl (GelMA) to form hydrogel via one-step UV light initiation. The hydrogel produced by this method has more uniform and well-crosslinked networks. The hydrogels demonstrated uniform porosity, adjustable hydrophilicity (water contact angle within 32.7-91.5°), and desired mechanical properties (maximum tensile strain of 242.8%, tensile strength of 75.9 kPa, and Young's modulus of 28.5 kPa). The hydrogel also possessed self-healing ability and pH sensitivity, showing higher mechanical tensile strength at lower pH. The temperature-adjustable viscosity of pre-gel solution (sol-gel transition point of 20.4 °C) endowed it to be 3D printed as a bioink, and the printed scaffold exhibited good resilience and toughness. Moreover, HUVEC, L929, and 3T3 cells were cultured on hydrogel surfaces for 28 days and were enveloped within the hydrogels for 3D culture, indicating excellent cytocompatibility of the hydrogels. Therefore, this hybrid hydrogel system can be used potentially in 3D cell culture and tissue engineering.

Review of Recent Advances and Their Improvement in the Effectiveness of Hydrogel-Based Targeted Drug Delivery: A Hope for Treating Cancer

Using hydrogels for delivering cancer therapeutics is advantageous in pharmaceutical usage as they have an edge over traditional delivery, which is tainted due to the risk of toxicity that it imbues. Hydrogel usage leads to the development of a more controlled drug release system owing to its amenability for structural metamorphosis, its higher porosity to seat the drug molecules, and its ability to shield the drug from denaturation. The thing that makes its utility even more enhanced is that they make themselves more recognizable to the body tissues and hence can stay inside the body for a longer time, enhancing the efficiency of the delivery, which otherwise is negatively affected since the drug is identified by the human immunity as a foreign substance, and thus, an attack of the immunity begins on the drug injected. A variety of hydrogels such as thermosensitive, pH-sensitive, and magnetism-responsive hydrogels have been included and their potential usage in drug delivery has been discussed in this review that aims to present recent studies on hydrogels that respond to alterations under a variety of circumstances in "reducing" situations that mimic the microenvironment of cancerous cells.

Cyclodextrin-Containing Hydrogels: A Review of Preparation Method, Drug Delivery, and Degradation Behavior

Hydrogels possess porous structures, which are widely applied in the field of materials and biomedicine. As a natural oligosaccharide, cyclodextrin (CD) has shown remarkable application prospects in the synthesis and utilization of hydrogels. CD can be incorporated into hydrogels to form chemically or physically cross-linked networks. Furthermore, the unique cavity structure of CD makes it an ideal vehicle for the delivery of active ingredients into target tissues. This review describes useful methods to prepare CD-containing hydrogels. In addition, the potential biomedical applications of CD-containing hydrogels are reviewed. The release and degradation process of CD-containing hydrogels under different conditions are discussed. Finally, the current challenges and future research directions on CD-containing hydrogels are presented.

Alginate hydrogels functionalized with β-cyclodextrin as a local paclitaxel delivery system

Modification of drug delivery materials with beta-cyclodextrins (β-CyD) is known to increase solubility of poorly water-soluble drugs, protect drugs from degradation and sustain release. In this study, we developed a hydrogel drug delivery system for local paclitaxel delivery using the natural polysaccharide alginate functionalized with β-CyD-moieties. Paclitaxel was chosen due to its ability to form inclusion complexes with cyclodextrins. The rheological and mechanical properties of the prepared hydrogels were characterized, as well as in vitro release of the paclitaxel and in vitro activity on PC-3 prostate cancer cells. Introduction of β-CyD-moieties into the hydrogel reduces the mechanical properties of the gels compared to nonmodified gels. However, gelation kinetics were not markedly different. Furthermore, the β-CyD-modified alginate helped to reduce undesired crystallization of the paclitaxel in the gel and facilitated paclitaxel diffusion out of the gel network. Remarkably, the β-CyD grafted alginate showed increased capacity to complex paclitaxel compared to free HPβ-CyD. Release of both paclitaxel and degradation products were measured from the gels and were shown to have cytotoxic effects on the PC-3 cells. The results indicate that functionalized alginate with β-CyDs has potential as a material for drug delivery systems.

Hydrogels and Their Applications in Targeted Drug Delivery

Conventional drug delivery approaches are plagued by issues pertaining to systemic toxicity and repeated dosing. Hydrogels offer convenient drug delivery vehicles to ensure these disadvantages are minimized and the therapeutic benefits from the drug are optimized. With exquisitely tunable physical properties that confer them great controlled drug release features and the merits they offer for labile drug protection from degradation, hydrogels emerge as very efficient drug delivery systems. The versatility and diversity of the hydrogels extend their applications beyond targeted drug delivery also to wound dressings, contact lenses and tissue engineering to name but a few. They are 90% water, and highly porous to accommodate drugs for delivery and facilitate controlled release. Herein we discuss hydrogels and how they could be manipulated for targeted drug delivery applications. Suitable examples from the literature are provided that support the recent advancements of hydrogels in targeted drug delivery in diverse disease areas and how they could be suitably modified in very different ways for achieving significant impact in targeted drug delivery. With their enormous amenability to modification, hydrogels serve as promising delivery vehicles of therapeutic molecules in several disease conditions, including cancer and diabetes.