Overview of polyethylene glycol-based materials with a special focus on core-shell particles for drug delivery application

Physico-Chemical Properties of Laponite®/Polyethylene-oxide Based Composites

This review aims to provide a literature overview as well as the authors' personal account to the studies of Laponite® (Lap)/Polyethylene-oxide (PEO) based composite materials and their applications. These composites can be prepared over a wide range of their mutual concentrations, they are highly water soluble, and have many useful physico-chemical properties. To the readers' convenience, the contents are subdivided into different sections, related with consideration of PEO properties and its solubility in water, behavior of Lap systems(structure of Lap-platelets, properties of aqueous dispersions of Lap and aging effects in them), analyzing ofproperties LAP/PEO systems, Lap platelets-PEO interactions, adsorption mechanisms, aging effects, aggregation and electrokinetic properties. The different applications of Lap/PEO composites are reviewed. These applications include Lap/PEO based electrolytes for lithium polymer batteries, electrospun nanofibers, environmental, biomedical and biotechnology engineering. Both Lap and PEO are highly biocompatible with living systems and they are non-toxic, non-yellowing, and non-inflammable. Medical applications of Lap/PEO composites in bio-sensing, tissue engineering, drug delivery, cell proliferation, and wound dressings are also discussed.

Targeted Bacterial Keratitis Treatment with Polyethylene Glycol-Dithiothreitol-Boric Acid Hydrogel and Gatifloxacin

INTRODUCTION/OBJECTIVE

To prolong the ocular residence time of gatifloxacin and enhance its efficacy against bacterial keratitis, this study developed a velocity-controlled polyethylene glycol-dithiothreitol-boric acid (PDB) hydrogel loaded with gatifloxacin.

METHODS

First, the basic properties of the synthesized PDB hydrogel and the gatifloxacin-loaded PDB hydrogel were assessed. Secondly, the in vitro degradation rate of the drug-loaded PDB was measured in a simulated body fluid environment with pH 7.4/5.5. The release behavior of the drug-loaded PDB was studied using a dialysis method with PBS solution of pH 7.4/5.5 as the release medium. Finally, a mouse model of bacterial keratitis was established, and tissue morphology was observed using hematoxylin-eosin staining. Additionally, mouse tear fluid was extracted to observe the antibacterial effect of the gatifloxacin-loaded PDB hydrogel.

RESULTS

The results showed that the PDB hydrogel had a particle size of 124.9 nm and a zeta potential of -23.3 mV, with good porosity, thermosensitivity, viscosity distribution, rheological properties, and high cell compatibility. The encapsulation of gatifloxacin did not alter the physical properties of the PDB hydrogel and maintained appropriate swelling and stability, with a high drug release rate in acidic conditions. Furthermore, animal experiments demonstrated that the gatifloxacin- loaded PDB hydrogel exhibited superior therapeutic effects compared to gatifloxacin eye drops and displayed strong antibacterial capabilities against bacterial keratitis.

CONCLUSION

This study successfully synthesized PDB hydrogel and developed a gatifloxacin drug release system. The hydrogel exhibited good thermosensitivity, pH responsiveness, stability, and excellent biocompatibility, which can enhance drug retention, utilization, and therapeutic effects on the ocular surface.

Applying in-situ visible photopolymerization for fabrication of electrospun nanofibrous carrier for meloxicam delivery

Despite meloxicam's many benefits, it will cause many drawbacks if the meloxicam release rate is not controlled. Accordingly, we introduced a technique based on the electrospinning process to control the release rate and also to reduce side effects. For this purpose, different nanofibers were used as drug couriers. Nanofibers were prepared using polyurethane, polyethylene glycol, and light curable poly (ethylene glycol) diacrylate (PEGDA) by electrospinning. In fact, light curable poly (ethylene glycol) diacrylate (PEGDA) was synthesized as a hydrophilic functional group. Next, PEGDA and polyurethane were used simultaneously to fabricate the drug carrier nanofiber in a single processing step, and the electrospinning apparatus was equipped with a blue light source for in-situ photopolymerization during the electrospinning process. The molecular structures of nanofibers and PEGDA were investigated by FT-IR, 1H NMR, 13C NMR, SEM, TEM, XRD, and DSC analyses. Finally, we reduced in vitro drug release to 44% within ten hours, while the minimum release of meloxicam from the tablet was 98%.

Strategies of stabilization of zein nanoparticles containing doxorubicin hydrochloride

Hybrid nanoparticles made up of zein and various stabilizers were developed and characterized. In detail, a zein concentration of 2 mg/ml was blended with various amounts of different phospholipids or PEG-derivatives in order to obtain formulations with suitable physico-chemical properties for drug delivery purposes. Doxorubicin hydrochloride (DOX) was used as a model of a hydrophilic compound and its entrapment efficiency, release profile and cytotoxic activity were investigated. Photon correlation spectroscopy showed that the best formulations were obtained using DMPG, DOTAP and DSPE-mPEG2000 as stabilizers of zein nanoparticles, which were characterized by an average diameter of ~100 nm, a narrow size distribution and a significant time- and temperature-dependent stability. The interaction between protein and stabilizers was confirmed through FT-IR analysis, while TEM analysis showed the presence of a shell-like structure around the zein core. The release profiles of the drug from the zein/DSPE-mPEG2000 nanosystems, evaluated at two pHs (5.5 and 7.4), showed a prolonged and constant leakage of the drug. The encapsulation of DOX within zein/DSPE-mPEG2000 nanosystems did not compromise its biological efficacy, demonstrating the potential application of these hybrid nanoparticles as drug carriers.

Shape programmable T1-T2 dual-mode MRI nanoprobes for cancer theranostics

The shape effect is an important parameter in the design of novel nanomaterials. Engineering the shape of nanomaterials is an effective strategy for optimizing their bioactive performance. Nanomaterials with a unique shape are beneficial to blood circulation, tumor targeting, cell uptake, and even improved magnetism properties. Therefore, magnetic resonance imaging (MRI) nanoprobes with different shapes have been extensively focused on in recent years. Different from other multimodal imaging techniques, dual-mode MRI can provide imaging simultaneously by a single instrument, which can avoid differences in penetration depth, and the spatial and temporal resolution of multiple imaging devices, and ensure the accurate matching of spatial and temporal imaging parameters for the precise diagnosis of early tumors. This review summarizes the latest developments of nanomaterials with various shapes for T1-T2 dual-mode MRI, and highlights the mechanism of how shape intelligently affects nanomaterials' longitudinal or transverse relaxation, namely sphere, hollow, core-shell, cube, cluster, flower, dumbbell, rod, sheet, and bipyramid shapes. In addition, the combination of T1-T2 dual-mode MRI nanoprobes and advanced therapeutic strategies, as well as possible challenges from basic research to clinical transformation, are also systematically discussed. Therefore, this review will help others quickly understand the basic information on dual-mode MRI nanoprobes and gather thought-provoking ideas to advance the subfield of cancer nanomedicine.

Magnetic boron nitride nanosheets-based on pH-responsive smart nanocarriers for the delivery of doxorubicin for liver cancer treatment

A new drug delivery system (DDS) type complexing magnetic nanoparticles (MNP) along with boron nanosheets (BNN) coated with a pH-responsive polymer-polyethylene glycol (PEG) for the manageable loading/release of the anti-cancerous drug, doxorubicin (DOX), was created (MNP-BNN-PEG-DOX). The X-ray diffraction patterns of the nanocomposites displayed wide diffraction peaks for BNN at 25.1° and 42.3°, belonging to the (002) and (100) planes, correspondingly. Additionally, the characteristic peaks of Fe₃O₄ appeared at 30.5°, 35.9°, 43.6°, 54.1°, 57.5°, and 63.2°, belonging to the (220), (311), (400), (422), (511), and (440) crystal planes, correspondingly. Moreover, the magnetic properties of the nanocomposites revealed that the MNP-BNN remained magnetic after coating with PEG. The saturation magnetization (Ms) of the uncoated-MNP-BNN and MNP-BNN-PEG-1 were 49.4 and 42.3 emu g^-1, respectively. Both in vitro and in vivo analyses shown that DDS might inhibit tumor growth, provoke cancer cell apoptosis, and reduce the cytotoxic effects of DOX. In vivo analysis demonstrated that after treatment with phosphate-buffered saline (PBS), MNP-BNN-PEG-1, free DOX, and MNP-BNN-PEG-1-DOX, the average tumor growth and weight were 1906, 1997, 1188, and 1043 nm and 0.17, 0.20, 0.13, and 0.07 g, respectively. The MNP-BNN-PEG-DOX nanoparticles could be an effective treatment and potential alternative for liver cancer therapy.

PEG Gels Significantly Improve the Storage Stability of Nucleic Acid Preparations

Currently, nucleic acid preparations have gained much attention due to their unique working principle and application value. However, as macromolecular drugs, nucleic acid preparations have complex construction and poor stability. The current methods to promote stability face problems such as high cost and inconvenient operatios. In this study, the hydrophilic pharmaceutical excipient PEG was used to gelate nucleic acid preparations to avoid the random movements of liquid particles. The results showed that PEG gelation significantly improved the stability of PEI25K-based and liposome-based nucleic acid preparations, compared with nucleic acid preparations without PEG gelation. After being stored at 4 °C for 3 days, non-PEG gelled nucleic acid preparations almost lost transfection activity, while PEGylated preparations still maintained high transfection efficiency. Fluorescence experiments showed that this effect was caused by inhibiting particle aggregation. The method described in this study was simple and effective, and the materials used had good biocompatibility. It is believed that this study will contribute to the better development of gene therapy drugs.