In vitro and in vivo evaluation of chitosan microspheres with different deacetylation degree as potential embolic agent.

To evaluate the potential of N-acetylated chitosan microspheres used as a chemoembolic agent in vivo and in vitro. Calibrated spherical chitosan microspheres (CMs) were prepared via Water-in-Oil emulsification method and CMs were acetylated (ACMs). The swelling rate of CMs was greatly affected by pH than that of ACMs and both of them affected by temperature. Microspheres with excellent thermal stability demonstrated controllable degradation in lysozyme solution. Doxorubicin was released from microspheres in vitro and exhibited excellent control release profile. ACMs caused hemolysis less than CMs (<5% of the time). Co-culture with mouse embryo fibroblasts revealed that microspheres have non-cytotoxic nature. Microspheres planted in a rat gluteal muscle demonstrated that it were biodegradable and biocompatible. ACMs were performed in rabbit ear embolization model and ischemic necrosis on ear was visible due to the vascular occlusion after 15 days. Acetylated chitosan microspheres could be used as potential biocompatible and biodegradable embolic agents.

Adsorption characteristics of residual oil on amphiphilic chitosan derivative.

In this study, a novel chitosan-based polymeric surfactant, H-Oleoyl-Carboxymethyl chitosan was used as a coagulation agent for cleaning residual oil. The characteristics of H-Oleoyl-Carboxymethyl chitosan were investigated by FTIR and XRD. And the adsorption capacities of chitosan and H-O-CMCS for removing the residue oil from the wastewater of oil extraction have been investigated. H-O-CMCS exhibited a greater rate than chitosan in cleaning the residual oil from the wastewater of oil extraction at the optimum conditions. Equilibrium study, Langmuir/Freundlich adsorption models and the pseudo first- and second-order kinetic models were applied to describe the mechanism of adsorption experiments. The experimental data fitted well with the Langmuir model and the second-order kinetic model. Regeneration studies, using by the roasting and rinsing method, were undergone for three successive adsorption/desorption processes. H-O-CMCS still retained the residual oil removal capacity after regeneration.

Injectable thermosensitive hydrogel based on chitosan and quaternized chitosan and the biomedical properties.

A novel injectable thermosensitive hydrogel (CS-HTCC/alpha beta-GP) was successfully designed and prepared using chitosan (CS), quaternized chitosan (HTCC) and alpha,beta-glycerophosphate (alpha,beta-GP) without any additional chemical stimulus. The gelation point of CS-HTCC/alpha beta-GP can be set at a temperature close to normal body temperature or other temperature above 25 degrees C. The transition process can be controlled by adjusting the weight ratio of CS to HTCC, or different final concentration of alpha,beta-GP. The optimum formulation is (CS + HTCC) (2% w/v), CS/HTCC (5/1 w/w) and alpha,beta-GP 8.33% or 9.09% (w/v), where the sol-gel transition time was 3 min at 37 degrees C. The drug released over 3 h from the CS-HTCC/alpha,beta-GP thermosensitive hydrogel in artificial saliva pH 6.8. In addition, CS-HTCC/alpha,beta-GP thermosensitive hydrogel exhibited stronger antibacterial activity towards two periodontal pathogens (Porphyromonas gingivalis, P.g and Prevotella intermedia, P.i). CS-HTCC/alpha, beta-GP thermosensitive hydrogel was a considerable candidate as a local drug delivery system for periodontal treatment.

Effect of cornuside on experimental sepsis.

This study was conducted to investigate the efficacy of cornuside, a secoiridoid glucoside compound, in cultured macrophages as well as in an experimental model of sepsis induced by cecal ligation and puncture (CLP) in rats. Cornuside was added to cultured macrophages at different concentrations, and all CLP rats were randomized to receive an intravenous injection of the corresponding drug followed by observation of its antisepsis effect. Our results showed that cornuside downregulated the levels of TNF- alpha, IL-6, and NO production in a dose-dependent manner in activated macrophages, while it upregulated the level of IL-10. Intravenous injection of cornuside or imipenem alone or in combination reduced CLP-induced lethality in rats after CLP. In addition, serum levels of TNF- alpha, IL-6, triggering receptor expressed on myeloid cells, and endotoxin were downregulated. On the other hand, the serum levels of IL-10 were upregulated. Decreased bacterial counts in blood, peritoneum, spleen, liver, and mesenteric lymph nodes and decreased myeloperoxidase in lung, liver, and small intestine also were found after cornuside injection. These data indicate that the antisepsis therapeutic effect of cornuside is mediated by decreased local and systemic levels of a wide spectrum of inflammatory mediators. This work provides first evidence for the clinic use of cornuside as a new immunomodulatory drug that has the capacity to inhibit the inflammatory response in sepsis.

Effects of scorpion venom bioactive polypolypeptides on platelet aggregation and thrombosis and plasma 6-keto-PG F1alpha and TXB2 in rabbits and rats.

Effects of scorpion venom active polypeptide (SVAP) from scorpion venom of Buthus Martensii Karsch of Chinese on platelet aggregation in ex vivo and vitro in rabbits, thrombosis in carotid artery of rats and plasma 6-keto-PG F1alpha and TXB2 in rats were studied by the turbidimetry, the duplicated thrombosis model by electrostimulation and RIA, respectively. The results showed that SVAP 0.125, 0.25, 0.5 mg/ml inhibited significantly the rabbit platelet aggregation triggered by 0.3 U/ml thrombin, 10 microM ADP in vitro (P<0.05 or 0.01) and SVAP at the dose of 0.32, 0.64 mg/kg iv prolonged distinctively the occlusion time of thrombosis that were induced by electrical stimulation. Increased% of 0.16, 0.32 and 0.64 mg/kg were 30.16, 71.74, 98.27%, respectively, which showed a good dose-effect relationship. SVAP 0.22 mg/ml (in vitro) or 0.2, 0.4 mg/kg (in ex vivo) could obviously increase the plasma concentration of 6-keto-PG F1alpha, but slightly effect rats plasma concentration of TXB2 in vitro and in ex vivo and significantly increase of value of PG I2/TXA2, which suggested that the mechanism of the antithrombotic action of SVAP is related to the resistance against platelet aggregation, increase of the concentration of PG I2 in plasma.