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The present study focused on the design and preparation of acid-responsive benzimidazole-chitosan quaternary ammonium salt (BIMIXHAC) nanogels for a controlled, slow-release of Doxorubicin HCl (DOX.HCl). The BIMIXHAC was crosslinked with sodium tripolyphosphate (TPP) using the ion crosslinking method. The method resulted in nanogels with low polydispersity index, small particle size, and positive zeta potential values, indicating the good stability of the nanogels. Compared to hydroxypropyl trimethyl ammonium chloride chitosan-Doxorubicin HCl-sodium tripolyphosphate (HACC-D-TPP) nanogel, the benzimidazole-chitosan quaternary ammonium salt-Doxorubicin HCl-sodium tripolyphosphate (BIMIXHAC-D-TPP) nanogel show higher drug encapsulation efficiency and loading capacity (BIMIXHAC-D-TPP 93.17 ± 0.27% and 31.17 ± 0.09%), with acid-responsive release profiles and accelerated release in vitro. The hydroxypropyl trimethyl ammonium chloride chitosan-sodium tripolyphosphate (HACC-TPP), and benzimidazole-chitosan quaternary ammonium salt-sodium tripolyphosphate (BIMIXHAC-TPP) nanogels demonstrated favorable antioxidant capability. The assay of cell viability, measured by the MTT assay, revealed that nanogels led to a significant reduction in the cell viability of two cancer cells: the human lung adenocarcinoma epithelial cell line (A549) and the human breast cancer cell line (MCF-7). Furthermore, the BIMIXHAC-D-TPP nanogel was 2.96 times less toxic than DOX.HCl to the mouse fibroblast cell line (L929). It was indicated that the BIMIXHAC-based nanogel with enhanced antioxidant and antitumor activities and acidic-responsive release could serve as a potential nanocarrier. [ABSTRACT FROM AUTHOR]

In this study, three series of chitosan derivatives bearing imidazole rings, including the Schiff‐bases of chitosan, N‐substituted chitosan, and quaternized chitosan are designed and synthesized. The structures of these chitosan derivatives are verified by FT‐IR and 1H NMR, and their antioxidant, antibacterial, and antifungal activities are tested. The Schiff‐bases of chitosan and N‐substituted chitosan have similar biological properties compared with chitosan. Derivatives 2IMTMC, 4IMTMC, MIMTMC, and BIMTMC exhibit significant antioxidant ability and antifungal activity, especially derivative BIMTMC. All the quaternized chitosan remarkably inhibits Escherichia coli, Staphylococcus aureus, and Vibrio harvey, especially derivative BIMTMC, whose minimum inhibitory concentration values are 0.03125, 0.0625, and 0.03125 mg mL−1, respectively. The results indicated that quaternized chitosan are synergistic with imidazole groups and have the better antioxidant, antifungal, and antibacterial properties than chitosan, which can be used as drug materials for antioxididant and antimicrobial purposes. [ABSTRACT FROM AUTHOR]

Excessive inorganic ions in vivo may lead to electrolyte disorders and induce damage to the human body. Therefore, preparation of enhanced bioactivity compounds, composed of activated organic cations and organic anions, is of great interest among researchers. In this work, glucosamine-heparin salt (GHS) was primarily synthesized with positively charged glucosamine hydrochloride (GAH) and negatively charged heparin sodium (Heps) by ion exchange method. Then, the detailed structural information of the GHS was characterized by FTIR, 1H NMR spectroscopy and ICP-MS. In addition, its anticoagulant potency and antioxidant properties were evaluated, respectively. The results demonstrated that GHS salt achieved enhanced antioxidant activities, including 98.78% of O2•− radical scavenging activity, 91.23% of •OH radical scavenging rate and 66.49% of DPPH radical scavenging capacity at 1.6 mg/mL, severally. Meanwhile, anticoagulant potency (ATTP) of GHS strengthened from 153.10 ± 17.14 to 180.03 ± 6.02 at 0.75 μmol/L. Thus, introducing cationic glucosamine residues into GHS could improve its anticoagulant activity. The findings suggest that GHS product with a small amount of inorganic ions can greatly abate the prime cost of antioxidants and anticoagulants, and has significant economic benefits and practical significance. [ABSTRACT FROM AUTHOR]

pH-responsive nanogels have played an increasingly momentous role in tumor treatment. The focus of this study is to design and develop pH-responsive benzimidazole-chitosan quaternary ammonium salt (BIMIXHAC) nanogels for the controlled release of doxorubicin hydrochloride (DOX) while enhancing its hydrophilicity. BIMIXHAC is crosslinked with carboxymethyl chitosan (CMC), hyaluronic acid sodium salt (HA), and sodium alginates (SA) using an ion crosslinking method. The chemical structure of chitosan derivatives was verified by 1H NMR and FT-IR techniques. Compared to hydroxypropyl trimethyl ammonium chloride chitosan (HACC)-based nanogels, BIMIXHAC-based nanogels exhibit better drug encapsulation efficiency and loading capacity (BIMIXHAC-D-HA 91.76 %, and 32.23 %), with pH-responsive release profiles and accelerated release in vitro. The series of nanogels formed by crosslinking with three different polyanionic crosslinkers have different particle size potentials and antioxidant properties. BIMIXHAC-HA, BIMIXHAC-SA and BIMIXHAC-CMC demonstrate favorable antioxidant capability. In addition, cytotoxicity tests showed that BIMIXHAC-based nanogels have high biocompatibility. BIMIXHAC-based nanogels exhibit preferable anticancer effects on MCF-7 and A549 cells. Furthermore, the BIMIXHAC-D-HA nanogel was 2.62 times less toxic than DOX to L929 cells. These results suggest that BIMIXHAC-based nanogels can serve as pH-responsive nanoplatforms for the delivery of anticancer drugs. [ABSTRACT FROM AUTHOR]

Herein, imidazole acids grafted chitosan derivatives were synthesized, including HACC, HACC derivatives, TMC, TMC derivatives, amidated chitosan and amidated chitosan bearing imidazolium salts. The prepared chitosan derivatives were characterized by FT-IR and 1H NMR. The tests evaluated the biological antioxidant, antibacterial, and cytotoxic activities of chitosan derivatives. The antioxidant capacity (DPPH radical, superoxide anion radical and hydroxyl radical) of chitosan derivatives was 2.4–8.3 times higher than that of chitosan. The antibacterial capacity against E. coli and S. aureus of cationic derivatives (HACC derivatives, TMC derivatives, and amidated chitosan bearing imidazolium salts) was more active than only imidazole-chitosan (amidated chitosan). In particular, the inhibition effect of HACC derivatives on E. coli was 15.625 μg/mL. Moreover, the series of chitosan derivatives bearing imidazole acids showed certain activity against MCF-7 and A549 cells. The present results suggest that the chitosan derivatives in this paper seem to be promising carrier materials for use in drug delivery systems. [Display omitted] [ABSTRACT FROM AUTHOR]