Zhengquan Su

Preparation and characterization of water-soluble chitosan nanoparticles as protein delivery system

The objective of this study was to investigate the potential of water soluble chitosan as a carrier in the preparation of protein-loaded nanoparticles. Nanoparticles were prepared by ionotropic gelation of water-soluble chitosan (WSC) with sodium tripolyphosphate (TPP). Bovine serum albumin (BSA) was applied as a model drug. The size and morphology of the nanoparticles were investigated as a function of the preparation conditions. The particles were spherical in shape and had a smooth surface. The size range of the nanoparticles was between 100 and 400 nm. Result of the in vitro studies showed that the WSC nanoparticles enhance and prolong the intestinal absorption of BSA. These results also indicated that WSC nanoparticles were a potential protein delivery system.

Preparation of Chitosan and Water-Soluble Chitosan Microspheres via Spray-Drying Method to Lower Blood Lipids in Rats Fed with High-Fat Diets.

This experiment aimed to investigate the effects of the chitosan (CTS) and water-soluble chitosan (WSC) microspheres on plasma lipids in male Sprague-Dawley rats fed with high-fat diets. CTS microspheres and WSC microspheres were prepared by the spray-drying technique. Scanning electron microscopy (SEM) micrographs showed that the microspheres were nearly spherical in shape. The mean size of CTS microspheres was 4.07 μm (varying from 1.50 to 7.21 μm) and of WSC microspheres was 2.00 μm (varying from 0.85 to 3.58 μm). The rats were classified into eight groups (n = 8) and were fed with high-fat diets for two weeks to establish the hyperlipidemic condition and were then treated with CTS microspheres and WSC microspheres, CTS and WSC for four weeks. The results showed that CTS and WSC microspheres reduced blood lipids and plasma viscosity and increased the serum superoxide dismutase (SOD) levels significantly. This study is the first report of the lipid-lowering effects of CTS and WSC microspheres. CTS and WSC microspheres were found to be more effective in improving hyperlipidemia in rats than common CTS and WSC.

Hypolipidemic effects of chitosan nanoparticles in hyperlipidemia rats induced by high fat diet.

The aim of this study was to investigate the hypolipidemic effects of chitosan nanoparticles(CTS-NP) preparations with ionotropic gelation, rotary evaporation, and spray-drying technique. Male SD (Sprague-Dawley) rats were separated into five groups, a normal diet group, a high fat emulsions group, a CTS control group and CTS-NP groups treated with two different doses of CTS-NP. The nanoparticles were spherical in shape and had a smooth surface. The size range of the nanoparticles was between 500 and 1000 nm. The apparent serum lipid and plasma viscosity in CTS-NP group was significantly lower than that in the CTS group, as well as the serum superoxide dismutate (SOD) levels was increased. Although no significant difference in adipose tissue was found among the groups, the rats fed on CTS-NP had lower relative liver weight and body weight when compared with those fed on normal diet. This study was the first report of the effects of CTS-NP in the hyperlipidemia rats, and suggests that the CTS-NP could be used for the treatment of hyperlipidemia.

Water-soluble chitosan nanoparticles inhibit hypercholesterolemia induced by feeding a high-fat diet in male sprague-dawley rats

Chitosan, a deacetylated product of chitin, has been demonstrated to lower cholesterol in humans and animals. However, chitosan is not fully soluble in water which would influence absorption in the human intestine. In addition, water-soluble chitosan (WSC) has higher reactivity compared to chitosan. The present study was designed to clarify the effects of WSC and water-soluble chitosan nanoparticles (WSC-NPs) on hypercholesterolemia induced by feeding a high-fat diet in male Sprague-Dawley rats. WSC-NPs were prepared by the ionic gelation method and the spray-drying technique. The nanoparticles were spherical in shape and had a smooth surface. The mean size of WSC-NPs was 650 nm variing from 500 to 800 nm. Results showed that WSC-NPs reduced the blood lipids and plasma viscosity significantly and increased the serum superoxide dismutase (SOD) activities significantly. This paper is the first report of the lipid-lowering effects of WSC-NPs suggesting that the WSC-NPs could be used for the treatment of hypercholesterolemia.

Antiobese Effects of Capsaicin–Chitosan Microsphere (CCMS) in Obese Rats Induced by High Fat Diet

Chitosan (CTS) and capsaicin (CAP) are two kinds of effective ingredients for antiobesity, which are extracted from crab shells and Capsicum annuum. However, the strong taste of CAP makes it difficult to consume, and the antiobesity ability of CTS is limited. In this study, we prepared capsaicin-chitosan microspheres (CCMSs) by ion-cross-linking and spray drying and examined the antiobesity ability of CCMSs in obese rats. The effects of CCMSs on body weight, Lees index, body fat, and serum lipids were investigated. The mRNA expression of PPARα, PPARγ, leptin, UCP2, GPR120, FTO, and adiponectin in the liver was determined by quantitative real-time PCR, and the protein expression of adiponectin, leptin, PPARα, UCP2, and hepatic lipase in serum was evaluated by enzyme-linked immunosorbent assay. CCMSs were prepared with 85.17% entrapment efficiency and 8.87% mean drug loading. Compared with chitosan microspheres, CAP, and Orlistat, the CCMSs showed better ability to control body weight, body mass index, organ index, body fat, proportion of fat to body weight, and serum lipids. The CCMSs upregulated the expressions of PPARα, PPARγ, UCP2, and adiponectin and downregulated the expression of leptin. CCMSs may thus be considered novel, safe, effective, and natural weight loss substances, and there is an additive effect between CTMS and capsaicin.

Effects of chitosan and water-soluble chitosan micro- and nanoparticles in obese rats fed a high-fat diet

Purpose: This study determined the effects of chitosan (CTS) and water-soluble chitosan (WSC) microparticles (MPs) and nanoparticles (NPs) in rats with high-fat diet-induced obesity. Methods: The rats were randomly separated into eight groups: a normal diet group (the blank control), a high-fat emulsion group (the negative control), CTS and WSC control groups, CTS-MP and WSC-MP groups, and CTS-NP and WSC-NP groups. All groups (except the blank control group) were fed the high-fat diet for 4 weeks to establish the obesity model. Different samples were administered orally once daily to the treatment groups for 4 weeks. Results: A significantly lower weight gain was observed in the WSC-MP and WSC-NP groups, as well as in the CTS-MP and CTS-NP groups, compared with rats given a normal diet and a high-fat diet (P < 0.05). The WSC-MP rats had the least weight gain among all the groups. The food intake in the eight groups had the same trend as weight gain. CTS and WSC MPs and NPs significantly reduced the final amounts of epididymal and perirenal white adipose tissue. Liver weight was reduced in the CTS-MP group compared to rats fed a high-fat diet. Serum total cholesterol and low-density lipoprotein cholesterol were significantly reduced in all treatment groups, with the WSC-MP and CTS-MP groups showing a more significant reduction than the other groups. Triacylglycerol levels were significantly reduced in the WSC-NP group compared to the high-fat group. The mortality rates of CTS-MP, CTS-NP, WSC-MP, and WSC-NP groups were 30%, 30%, 55%, and 65%, respectively. The median lethal dose for the WSC-MP and WSC-NP groups were 4080 mg/kg and 2370 mg/kg, respectively. Conclusion: These results indicate that CTS and WSC MPs and NPs have greater effects than commercially available CTS and WSC, and can be used as potential antiobesity agents.

Preparation and characterization of water-soluble chitosan microparticles loaded with insulin using the polyelectrolyte complexation method

Polymeric delivery systems based on microparticles have emerged as a promising approach for peroral insulin delivery. The amount of insulin was quantified by the improved Bradford method. It was shown that water-soluble chitosan/insulin/tripolyphosphate (TPP) mass ratio played an important role in microparticles formation. Stable, uniform, and spherical water-soluble chitosan microparticles (WSC-MPs) with high insulin association efficiency were formed at or close to optimized WSC/insulin/TPP mass ratio. WSC-MPs had higher association efficiency in the pH 4.0 and pH 9.7 of TPP solution. The results showed that association efficiency and loading capacity of insulin-loaded WSC-MPs prepared in 0.01mol/L HCl of insulin were 48.28 ± 0.90% and 9.52 ± 1.34%. The average size of insulin-loaded WSC-MPs was 292 nm. The presented WSC microparticulate system has promising properties towards the development of an oral delivery system for insulin.

Development and validation of an improved Bradford method for determination of insulin from chitosan nanoparticulate systems

Context: Blank chitosan nanoparticles are currently used as reference for the calibration curve, which fails to resolve the supernatant of the nanoparticles in the interference of Coomassie Brilliant Blue G-250 reagent; supernatants are generated at different chitosan nanoparticulate prescriptions, which have different interferences. There are notable errors in the experimental results, and the method is not feasible. Objective: In this study, an improved, rapid, and economic Bradford method was developed and validated. Materials and methods: The pH of the supernatant of blank chitosan nanoparticles was adjusted to 7–9 through adding saturated NaOH. The precipitation (free chitosan) in the solution was separated by centrifuging for about 10 min (4000 r/min). Results: The method eliminated the interference of free chitosan of different prescriptions. The results showed that the method presented a linearity in the range of 50–300 μg/mL (R2 = 0.9992), and possessed a good inter-day and intra-day precision based on relative standard deviation values (less than 3.10%). Recovery of the supernatant of blank chitosan nanoparticles was between 98.30 and 99.93%, and the recovery of blank chitosan nanoparticles was between 95.57 and 100.27%. Discussion and conclusion: The method was further tested for determination of the association efficiency of insulin to nanoparticulate carriers composed of chitosan. Encapsulant release under simulated gastrointestinal fluids was evaluated.