N-succinyl chitosan-oxidized hyaluronic acid-calcium chloride hydrogel as hemostatic agent.

This study aims to develop an effective hemostatic agent in the management of irregular and deep wounds that can accelerate the hemostatic process. The background revealed the importance of rapid treatment of bleeding, with data showing a significant risk of death from blood loss. Current treatments use conventional hemostatic dressings, but they are less effective on irregular surgical wounds. Several studies have developed chitosan, hyaluronic acid, and CaCl2-based hydrogels that have hemostatic, regenerative, and antibacterial potential. However, there is still a need to develop hydrogels that are thermally stable, biocompatible, and able to accelerate the hemostatic process. This research will synthesize self-healing hydrogels by modifying the structure of chitosan and hyaluronic acid, using a certain ratio of ingredients. The research procedure was carried out with the preparation of N-succinyl chitosan (NSC) and oxidized hyaluronic acid (OHA) as the main ingredients which were then added with CaCl2 to produce self-healing injectable hydrogel. First, NSC and OHA were dissolved in phosphate buffer solution (pH = 7.4 PBS) to obtain 60 mg/mL NSC and OHA solution respectively. Calcium chloride was then dissolved in water to obtain 120 mg/mL CaCl2 solution. Then NSC-OHA-CaCl2-based hydrogels were synthesized through rapid and full solution mixing above room temperature with the composition of (1-1-0.1; 1-1-0.2; and 1-1-0.3). The targeted findings of this research are sample characterization results that explain and prove the best NSC-OHA-CaCl2 composition variation that can be used as a hemostatic agent for irregular and deep wounds. The results of the analysis obtained FTIR test data with the formation of C = N functional groups in the four samples; blood clotting time test for sample K0, K1, K2, and K3 with time 4.6, 3.33, 2.66, and 1 s; MTT assay with cell viability percentage of 77.82% for sample K0, 84.18% for sample K1, 89.30% for sample K2, and 89.50% for sample K3; hemolysis index percentage of 0.373% for sample K0, 0.555% for sample K1, 0.625% for sample K2, and 0.201% for sample K3; Viscosity test obtained data of 13 dPa s for sample K0, 15 dPa s for sample K1, 16 dPa s for sample K2, and 18 dPa. The injectability test yielded an injectability percentage of 96.84% for sample K0, 95.03% for sample K1, 94.78% dPa s for sample K2, and 94.61% for sample K3; the DSC test results of the four samples obtained a transition peak at the exothermic peak of 62.27°C for sample K0, 70.23°C for sample K1, 73.77°C for sample K2, and 74.49°C for sample K3; and the characteristic graph of the TGA test results, the weight profile of the hydrogel during heating which showed a mass change of 21.64 mg in sample K0, 16.89 mg in sample K1, 15.37 mg in sample K2, and 11.43 mg in sample K3 (°C).

Fabrication of In Situ-Cross-Linked N-Succinyl Chitosan/Oxidized Alginate Hydrogel-Loaded Ascorbic Acid and Biphasic Calcium Phosphate for Bone Tissue Engineering.

Bone tissue engineering is a promising technology being studied globally to become an effective and sustainable method to treat the problems of damaged or diseased bones. In this work, we developed an in situ cross-linking hydrogel system that combined N-succinyl chitosan (NSC) and oxidized alginate (OA) at varying mixing ratios through Schiff base cross-linking. The hydrogel system also contains biphasic calcium phosphate (BCP) and ascorbic acid (AA), which could enhance biological characteristics and accelerate bone repair. The hydrogels' properties were examined through physicochemical tests such as scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), x-ray diffraction (XRD), pore size and porosity measurement, swelling ratio, degradation rate, AA release study, as well as cytocompatibility, including live/dead and cytotoxicity assays. The results revealed that the supplementation of AA and BCP components can affect the physico-mechanical properties of the hydrogel system. However, they exhibited noncytotoxic properties. Overall, the results demonstrated that the hydrogel composed of 3% (w/v) NSC and 3% (w/v) OA (NSC: OA volume ratio is 8:2) loaded with 40% (w/w) BCP and 0.3 mg/mL AA has the potential for bone regeneration.

N-succinyl-chitosan as ecofriendly pesticide carriers: Nano encapsulation and synergistic antifungal effect on 4-hydroxyphenyl-2-propenyl-1-one derivatives based on chalcone structure.

INTRODUCTION: Traditional pesticides have poor-water solubility, high toxicity and low bioavailability. Therefore, it is of great significance for the sustainable and healthy development of the pesticide industry to develop efficient and ecofriendly new chemical pesticide products and formulations. OBJECTIVES: This study aims to synthesize a series of derivatives based on chalcone structure (HPPO), and then use the amphiphilic and self-assembly characteristics of N-succinyl-chitosan (NSCS) to prepare HPPO@NSCS nanoparticles (HPPO@NSCS NPs) in order to realize the green application of HPPO, and investigate the antifungal activity and mechanisms of HPPO@NSCS NPs. METHODS: NSCS was synthesized by structural modification using chitosan as the carrier. Based on its amphiphilic and self-assembly characteristics, HPPO-16@NSCS NPs were reasonably prepared by combining with active small molecule HPPO-16. Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), dynamic light scattering (DLS), fluorescence spectroscopy (FS) and high-performance liquid chromatography (HPLC) were used to characterize the physicochemical properties of NSCS and HPPO-16@NSCS NPs. The inhibitory activity of nanopesticides against Rhizoctonia solani (R. solani) was tested in vivo and in vitro. The mechanism of antifungal action was discussed from the observation of pathogen morphology, fluorescence staining and enzyme activity determination. RESULTS: 28 small molecules based on chalcone structure (HPPO-1-28), NSCS and HPPO-16@NSCS were successfully synthesized. The application of HPPO-16@NSCS could impair the development, cell structure, cellular energy utilization, and metabolism pathways of the fungi. The protective effects of HPPO-16@NSCS NPs on rice leaves and leaf sheaths were 80.9 and 76.1 %, respectively, which were better than those of azoxystrobin. CONCLUSION: This study reveals that these simple chalcone derivatives can be further explored as viable antibacterial alternatives and NSCS as a novel pesticide matrix can be used for the delivery of more insoluble pesticides.

Design of a delivery vehicle chitosan-based self-assembling: controlled release, high hydrophobicity, and safe treatment of plant fungal diseases.

BACKGROUND: Traditional pesticides are poorly water-soluble and suffer from low bioavailability. N-succinyl chitosan (NSCS) is a water-soluble chitosan derivative, has been recently used to encapsulate hydrophobic drugs to improve their bioavailability. However, it remains challenging to synthesize pesticides of a wide variety of water-soluble drugs and to scale up the production in a continuous manner. RESULTS: A synthetic method for preparing water-soluble nanopesticides with a polymer carrier was applied. The bioactive molecule BTL-11 was loaded into hollow NSCS to promote drug delivery, improve solubility and anti-fungal activity. The synthesized nanopesticides had well controlled sizes of 606 nm and the encapsulation rate was 80%. The release kinetics, drug toxicity and drug activity were further evaluated. The inhibitory activity of nanopesticides against Rhizoctonia solani (R. solani) was tested in vivo and in vitro. In vivo against R. solani trials revealed that BTL-11 has excellent control efficiency for cultivated rice leaf and sheath was 79.6 and 76.5%, respectively. By contrast, for BTL-11@NSCS NPs, the anti-fungal ability was strongly released and afforded significant control efficiencies of 85.9 and 81.1%. Those effects were significantly better than that of the agricultural fungicide azoxystrobin (51.5 and 66.5%). The proposed mechanism was validated by successfully predicting the synthesis outcomes. CONCLUSIONS: This study demonstrates that NSCS is a promising biocompatible carrier, which can enhance the efficacy of pesticides, synergistically improve plant disease resistance, protect crop growth, and can be used for the delivery of more insoluble pesticides.

Preparation and physicochemical characterization of N-succinyl chitosan-coated liposomes for oral delivery of grape seed extract and evaluation of its effect on pulmonary fibrosis induced by bleomycin in rats.

Objectives: This study aimed to develop an oral succinyl chitosan-coated liposomal formulation containing grape seed extract and assess its therapeutic efficacy in rats with bleomycin-induced pulmonary fibrosis. Materials and Methods: N-succinyl chitosan was synthesized, and the liposomal formulations were prepared and characterized regarding phenolic content assay and morphology. Size, zeta potential, in vitro drug release, and stability. Pulmonary fibrosis was induced by intratracheal bleomycin injection, and hydroxyproline measurements, lung weight, animal body weight, as well as histopathological studies were performed. Results: Succinyl chitosan increases the physical stability of the formulation, especially in acidic conditions. Drug release studies revealed that 66.27% of the loaded drug was released from CF2 in an acidic medium in 2 hr, but 92.31% of the drug was released in 8 hr in a pH=7 medium. An in vivo study demonstrated that rats exposed to bleomycin significantly lost weight, while those treated with CF2 (400 mg/kg) partially regained weight. Bleomycin treatment increased the mean lung weight and the amount of hydroxyproline in the lungs; these values were significantly decreased in the group treated with 400 mg/kg CF2 (P<0.05). Histopathological examination confirmed that treatment with 400 mg/kg CF2 improved lung fibrosis. Conclusion: In rats, oral administration of N-succinyl chitosan-coated liposomes containing grape seed extract at the 400 mg/kg dose ameliorates bleomycin-induced pulmonary fibrosis.

Effects of N-succinyl-chitosan coating on properties of astaxanthin-loaded PEG-liposomes: Environmental stability, antioxidant/antibacterial activities, and in vitro release.

Astaxanthin (AST) has outstanding antioxidant and anti-inflammation bioactivities, but the low biocompatibility and stability limit its application in foods. In this study, N-succinyl-chitosan (NSC)-coated AST polyethylene glycol (PEG)-liposomes were constructed to enhance the biocompatibility, stability, and intestinal-targeted migration of AST. The AST NSC/PEG-liposomes were uniform in size, had larger particles, greater encapsulation efficiency, and better storage, pH, and temperature stability than the AST PEG-liposomes. AST NSC/PEG-liposomes exerted stronger antibacterial and antioxidant activities against Escherichia coli and Staphylococcus aureus than AST PEG-liposomes. The NSC coating not only protects AST PEG-liposomes from gastric acid but also prolongs the retention and sustained release of AST NSC/PEG-liposomes depending on the intestinal pH. Moreover, caco-2 cellular uptake studies showed that AST NSC/PEG-liposomes had higher cellular uptake efficiency than AST PEG-liposomes. And AST NSC/PEG-liposomes were taken up by caco-2 cells through clathrin mediated endocytic, macrophage pathways and paracellular transport pathway. These results further proved that AST NSC/PEG-liposomes delayed the release and promoted the intestinal absorption of AST. Hence, AST PEG-liposomes coated with NSC could potentially be used as an efficient delivery system for therapeutic AST.

Multichannel nerve conduit based on chitosan derivates for peripheral nerve regeneration and Schwann cell survival.

In this study, a chitosan-based composite multichannel nerve conduit consisting of a warp-knitted chitosan scaffold and internally oriented N-succinyl-chitosan (NS-chitosan) fibers was applied to bridge a 10-mm nerve defect in rats. This study confirmed that an external pipeline with appropriate mechanical support was obtained by warp knitting techniques and that NS-chitosan fibers were not toxic to L-929 and PC-12 cells. These fibers degraded slowly for over 90 days and exerted sustained neuroprotective effects on peripheral nerves through their ability to drive cellular migration, promote survival, and block apoptosis of damaged Schwann cells through the Bcl-2/Bax/caspase-3 pathway. The multichannel chitosan/NS-chitosan conduit represented a histologically and functionally successful nerve reconstruction across a damaged 10-mm peripheral nerve model, showing regenerative efficacy equal to that of an autograft. The results demonstrated that the chitosan/NS-chitosan conduit with a warp-knitted tube construct and aligned inner fiber had good mechanical and bioactive properties for nerve repair.

Preparation of a novel glucose oxidase-N-succinyl chitosan nanospheres and its antifungal mechanism of action against Colletotrichum gloeosporioides.

In this work, a new glucose oxidase-N-succinyl chitosan (GOD-NSCS) nanospheres was prepared through the immobilization of glucose oxidase (GOD) on N-succinyl chitosan (NSCS) nanospheres. Compared to the free GOD, GOD-NSCS nanospheres demonstrated the excellent anti-Colletotrichum gloeosporioides activity with the EC50 values of 211.2 and 10.7 µg/mL against mycelial growth and spores germination. The computational biology analysis demonstrated that the substrate presented the similar binding free energy with GOD-NSCS nanospheres (-27.64 kcal/mol) compared with the free GOD (-24.04 kcal/mol), indicating that GOD-NSCS nanospheres had the same oxidation efficiency and produced more H2O2. Moreover, the enzyme activity stability of GOD-NSCS nanospheres could be prolonged to 10 d. The cell membrane was destructed by the treatment of H2O2 produced by GOD, leading to the cell death. In vivo test, GOD-NSCS nanospheres treatment significantly prolonged the preservation period of mangoes 2-fold. Collectively, these results suggested that GOD-NSCS nanospheres suppresses anthracnose in postharvest mangoes by inhibiting the growth of C. gloeosporioides and might become a potential natural preservative for fruits and vegetables.

Dynamic and Self-Healable Chitosan/Hyaluronic Acid-Based In Situ-Forming Hydrogels.

In situ-forming, biodegradable, and self-healing hydrogels, which maintain their integrity after damage, owing to dynamic interactions, are essential biomaterials for bioapplications, such as tissue engineering and drug delivery. This work aims to develop in situ, biodegradable and self-healable hydrogels based on dynamic covalent bonds between N-succinyl chitosan (S-CHI) and oxidized aldehyde hyaluronic acid (A-HA). A robust effect of the molar ratio of both S-CHI and A-HA was observed on the swelling, mechanical stability, rheological properties and biodegradation kinetics of these hydrogels, being the stoichiometric ratio that which leads to the lowest swelling factor (×12), highest compression modulus (1.1·10−3 MPa), and slowest degradation (9 days). Besides, a rapid (3 s) self-repairing ability was demonstrated in the macro scale as well as by rheology and mechanical tests. Finally, the potential of these biomaterials was evidenced by cytotoxicity essay (>85%).

New injectable chitosan-hyaluronic acid based hydrogels for hemostasis and wound healing.

It is a challenge to develop hemostatic and wound dressings that are used for irregular shape and deep wound. Herein, a series of novel N-succinyl chitosan-oxidized hyaluronic acid based (NSC-OHA-based) hydrogels were fabricated, while calcium ions (Ca2+) and/or four-armed amine-terminated poly(ethylene glycol) (4-arm-PEG-NH2, labeled as PEG1) were introduced to regulate the mechanical behavior and bioactivities. We found all NSC-OHA-based hydrogels displayed self-healing and injectable performances. Besides, the addition of Ca2+ or PEG1 exhibited a positive effect on the adjustable mechanical behavior of hydrogels, providing the possibility to meet different mechanical requirements. Furthermore, Ca2+ or PEG1 significantly improved the biocompatibility, hemostasis and wound healing abilities of NSC-OHA hydrogel. Notably, compared with the commercial hemostatic agent (Arista™), hydrogels containing Ca2+ showed comparable hemostatic effects and significantly accelerated wound healing. Overall, the calcium-containing NSC-OHA hydrogels are promising for hemostasis and accelerating wound healing.

Enhanced photodynamic therapy of TiO2/N-succinyl-chitosan composite for killing cancer cells

Abstract The aim of this study was to investigate the effect of TiO2/N-succinyl-chitosan composite (TiO2/ NSCS) photodynamic therapy (PDT), while considering the effects of various light sources on the activation of photosensitizer. The methyl thiazolyl tetrazolium assay was used to examine the cell survival rate of the cells. The results showed that glioma cell strain (U251) was the most sensitive cancer cell strain to TiO2/NSCS. When the concentration of TiO2/NSCS was between 0 and 800 μg·mL-1, there was no obvious cytotoxicity to normal liver cells (HL-7702) and U251 cells. During the PDT process, the photokilling effect of TiO2/NSCS on U251 cells under ultraviolet-A (UVA) light irradiation was stronger than that of pure TiO2, and its killing effects were positively correlated with concentration and irradiation time. In addition, both UVA and visible light could excite TiO2/ NSCS, which had significant killing effect on U251 cells. The results of acridine orange/ethidium bromide fluorescent double staining and Annexin V/propidium iodide double staining indicated that TiO2/NSCS under UVA and visible light irradiation could kill U251 cells by inducing apoptosis, and the apoptosis rate of TiO2/NSCS treatment groups was higher than that of TiO2 treatment groups. Therefore, TiO2/NSCS might be used as a potential photosensitizer in PDT.

Preparation and characterization of succinyl chitosan and succinyl chitosan nanoparticle film: In vitro and in vivo evaluation of wound healing activity.

Development of novel wound dressing materials having the ability to prevent bacterial infections and capable of accelerating the tissue regeneration process is utmost important, since the wounds in patients can cause severe health issues. In the present work, we synthesized novel N-succinyl chitosan nanoparticles (N-SuC NPs) films and tested their antimicrobial, cytotoxicity, and in vitro and in vivo wound healing activity. N-SuC NPs were synthesized by ionic gelation method, and subsequently N-SuC NPs films were prepared by solution casting method using synthesized N-SuC NPs. The prepared N-SuC NPs films showed significant antimicrobial activity against Escherichia coli and Staphylococcus aureus with a minimum inhibitory concentration of 6 mg/mL and <8 mg/mL, respectively. The biocompatibility and the in vitro wound healing activity of N-SuC NPs films were analyzed using human dermal fibroblast (HDF) cells. In vivo cutaneous wound healing of the N-SuC NPs film was investigated using the Wister rat model, and the studies showed that the N-SuC NPs film significantly accelerated the wound healing process by inducing more blood vessels formation and tissue granulation. The experimental results showed that synthesized N-SuC NPs film had excellent antimicrobial, cytotoxicity and wound healing activity, indicating that it could be used in biomedical applications.

Preparation and properties of polyvinyl alcohol/N-succinyl chitosan/lincomycin composite antibacterial hydrogels for wound dressing.

Hydrogels are three-dimensional polymeric networks capable of absorbing large amounts of water or biological fluids with the properties resembling natural living tissues. Herein, polyvinyl alcohol (PVA)/N-succinyl chitosan (NSCS)/lincomycin hydrogels for wound dressing were prepared by the freezing/thawing method, then characterized by FTIR, SEM, and TGA. The compression strength, swelling behavior, water retention capacity, antibacterial activity, drug release and cytotoxicity were systematically investigated. The results showed that the introduction of NSCS remarkably enhanced the swelling capacity, leading to the maximum swelling ratio of 19.68 g/g in deionized water. The optimal compression strength of 0.75 MPa was achieved with 30 % NSCS content.Additionally, the incorporation of lincomycin brought a remarkable antibacterial activity against both Escherichia coli and Staphylococcus aureus. Specifically, 77.71 % of Staphylococcus aureus was inhibited with 75 µg/mL lincomycin, while the MTT assay demonstrated the nontoxic nature of the composite hydrogels. In summary, this PVA/NSCS/lincomycin hydrogel showed promising potential for wound dressing.

Study on TEMPO-Mediated Oxidation of N-Succinyl Chitosan and the Water Retention Property.

C-6 oxidized chitosan is of great interest in obtaining a new moisture retention polymer like hyaluronic acid. The direct C-6 specific oxidation of chitosan mediated by the TEMPO/NaClO/NaBr system has proven to be difficult because of the high crystalline and high C-2 amino group content. In this work, the pre-modification of chitosan by N-succinylation was investigated and followed by the TEMPO-mediated C-6 specific oxidation under homogeneous conditions. The desired 6-oxidized N-succinyl chitosan product was obtained within 15 min with a yield of about 92%. The structure of these chitosan derivatives was confirmed by FTIR and NMR spectroscopy. Moreover, it was observed that the selective oxidation led to a great improvement in water solubility and moisture retention ability. These results present a wide range of possibilities for expanding the utilization of chitosan resources.

Succinyl chitosan gold nanocomposite: Preparation, characterization, in vitro and in vivo anticandidal activity.

Herein, we have successfully synthesized a novel N-Succinyl chitosan/gold nanocomposite (N-SuC/Au NC) using N-SuC and gold(III) chloride, and investigated the biocompatibility and antifungal activity. The synthesized N-SuC/Au NC was characterized by UV-visible spectroscopy, X-ray diffraction, field emission scanning electron microscope, and inductively coupled plasma atomic emission spectroscopy. The N-SuC/Au NC exhibited a strong inhibition effect towards pathogenic Candida albicans. Morphological analysis revealed the destruction of C. albicans cell membrane due to N-SuC/Au NC treatment. The in vitro and in vivo toxicity of N-SuC/Au NC was analyzed with HEK293T mammalian cells and zebrafish larvae, respectively. The synthesized N-SuC/Au NC demonstrated no cytotoxicity towards HEK293T cells up to 1200 µg/mL concentration. The survival rate of the zebrafish larvae at 120 hpf, was found as 100% up to 1200 µg/mL of N-SuC/Au NC exposure. The in vivo studies further confirmed the inhibitory effects of N-SuC/Au NC on the formation of C. albicans hyphae in infected zebrafish muscle tissue.

A Novel pH- and Salt-Responsive N-Succinyl-Chitosan Hydrogel via a One-Step Hydrothermal Process.

In this study, we synthesized a series of pH-sensitive and salt-sensitive N-succinyl-chitosan hydrogels with N-succinyl-chitosan (NSCS) and the crosslinker glycidoxypropyltrimethoxysilane (GPTMS) via a one-step hydrothermal process. The structure and morphology analysis of the NSCS and glycidoxypropyltrimethoxysilane-N-succinyl chitosan hydrogel (GNCH) revealed the close relation between the swelling behavior of hydrogels and the content of crosslinker GPTMS. The high GPTMS content could weaken the swelling capacity of hydrogels and improve their mechanical properties. The hydrogels show high pH sensitivity and reversibility in the range of pH 1.0 to 9.0, and exhibit on-off switching behavior between acidic and alkaline environments. In addition, the hydrogels perform smart swelling behaviors in NaCl, CaCl2, and FeCl3 solutions. These hydrogels may have great potential in medical applications.

Rheological behavior of biodegradable N-succinyl chitosan-g-poly (acrylic acid) hydrogels and their applications as drug carrier and in vitro theophylline release.

Novel pH sensitive N-succinyl chitosan-g-poly (acrylic acid) hydrogels were synthesized through free radical mechanism. Rheometer was used to observe the mechanical strength of the hydrogels. In vitro degradation was conducted in SIF (pH 7.4). The effect of concentration of monomers, initiator, and crosslinking agent and pH and ionic strength of NaCl, CaCl2, and AlCl3 on swelling of the hydrogels was observed. The results showed that equilibrium swelling ratio was highly influenced by concentration of monomers, initiator, and crosslinking agent concentration, and pH and salt solutions of NaCl, CaCl2, and AlCl3. The swelling kinetics revealed that swelling followed non-Fickian anomalous transport. Furthermore, theophylline loading (DL %) and encapsulation efficiency (EE %) of the hydrogels was in the range of 15.5 ±â€¯0.15-22.8 ±â€¯0.06% and 62 ±â€¯0.15-91 ±â€¯0.26%, respectively. The release of theophylline in physiological mediums was strongly influenced by the pH. The theophylline release was in the range of 51 ±â€¯0.20-92 ±â€¯0.12% in SIF and 7.4 ±â€¯0.02-14.9 ±â€¯0.03% in SGF (pH 1.2), respectively. The release data fitted well to Korsmeyer-Peppas model. The chemical activity of the theophylline suggested that drug maintained its chemical activity after release in vitro. The results suggest that synthesized hydrogels are excellent drug carriers.

Preparation and characterization of C-phycocyanin peptide grafted N-succinyl chitosan by enzyme method.

C­phycocyanin peptide (CPC) grafted N­succinyl chitosan (NSC) was prepared via the catalysis of Microbial transglutaminase (MTGase). The single factor experiment displayed that the degree of substitution (DS) of N­succinyl chitosan­C­phycocyanin peptide (NSC­CPC) depended on the reaction time, the reaction temperature and the reaction pH value. The CS, synthesized NSC and NSC­CPC were characterized by Fourier transform infrared spectroscopy (FT-IR). NSC­CPC showed excellent moisture absorption and retention ability. In vitro antioxidant activity assays demonstrated that, with the DS and concentration increasing of NSC­CPC, the scavenging activity of 1,1­Diphenyl­2­pic­rylhydrazyl (DPPH) radical and hydroxyl radical increased. The methylthiazol tetrazolium (MTT) essay demonstrated that NSC­CPC inhibited Hela cells while promoted the proliferation of L929 mouse fibroblasts. In conclusion, these results suggested the potential application of NSC­CPC in pharmaceutical and biomedical fields.

Surfactant-stable and pH-sensitive liposomes coated with N-succinyl-chitosan and chitooligosaccharide for delivery of quercetin.

Layer-by-layer (LbL) self-assembly of multilayered liposomes is used to improve the stability of conventional liposomes. In this study, the LbL technology was used to prepare novel multilayered liposomes from chitooligosaccharide and N-succinyl-chitosan. We propose that this preparation can be used as a transdermal drug delivery system (TDDS) to enhance stability against surfactants and control drug release. Particle size increased with the number of layers in the multilayer and the zeta potential varied between positive and negative values with alternate deposition of polyelectrolytes. Finally, approximately 300-400nm-thick four-layered liposomes were prepared. These liposomes were more stable against surfactants and showed a relatively high release of quercetin at pH 5.5 than the uncoated liposomes as assessed via in vitro drug release and skin permeation studies. In summary, the multilayered liposomes showed potential for use as a surfactant-stable TDDS that effectively enhanced the permeation of quercetin, a poorly soluble drug, into the skin.

Toxicity of N-Succinyl-Chitosan to Bovine Hemoglobin and Human Liver Cells / 中国药学杂志

OBJECTIVE: To investigate the toxicity of N-succinyl-chitosan (NSCS) to bovine hemoglobin (BHb) and human liver cells (HL-7702). METHODS: BHb was used as a research object and the toxic effect of NSCS was investigated by UV-Vis absorption spectroscopy, fluorescence spectroscopy and synchrotron spectroscopy under the simulative human physiological condition. At the same time, human HL-7702 cells was used as a research object and methyl thiazolyl tetrazolium (MTT) assay was employed to examine the cytotoxicity of NSCS. RESULTS: The results of UV-Vis absorption spectroscopy and MTT showed that the toxicity of NSCS was weak, and substitution degree had little effect on it. The result of fluorescence spectroscopy demonstrated that the intrinsic fluorescence of BHb was quenched by NSCS and the quenching effect slightly increased with the increase of substitution degree. The quenching mechanism was mainly dynamic quenching, and the major driving forces were hydrophobic and electrostatic force. CONCLUSION: The result of synchronous fluorescence spectroscopy reveals that NSCS has almost no influence on the conformation of BHb. The toxicity of NSCS to BHb and HL-7702 is weak.