Physical Properties and Molecular Behavior of Chitosan Films

Chitosan films, varying in molecular weight and degree of deacetylation, were prepared by a casting technique using acetic acid as a dissolving vehicle. The physicochemical properties of the films were characterized. Both molecular weight and degree of deacetylation affected the film properties. Powder X-ray diffraction patterns and differential scanning calorimetry thermograms of all chitosan films indicated their amorphous state to partially crystalline state with thermal degradation temperature lower than 280–300°C. The increase in molecular weight of chitosan would increase the tensile strength and elongation as well as moisture absorption of the films, whereas the increase in degree of deacetylation of chitosan would either increase or decrease the tensile strength of the films depending on its molecular weight. Moreover, the higher the degree of deacetylation of chitosan the more brittle and the less moisture absorption the films became. All chitosan films were soluble in HCl–KCl buffer (pH 1.2), normal saline, and distilled water. They swelled in phosphate buffer (pH 7.4), and cross-linking between chitosan and phosphate anions might occur. Finally, transmission infrared and ¹³C-NMR spectra supported that chitosan films prepared by using acetic acid as a dissolving were chitosonium acetate films.     

Effect of heat on characteristics of chitosan film coated on theophylline tablets

The effect of heat on the characteristics of chitosan film coated on theophylline tablets was studied. Chitosan of high viscosity grade with molecular weight in the range of 800,000-1,000,000, 80-85% degree of deacetylation was used as a film former by dissolving in 1% v/v acetic acid solution. The coated tablets had been cured at 40, 60, and 100°C for 6, 12, and 24 hr. The morphology of the film at the edge and surface of coated tablets was investigated using scanning electron microscopy. Film cracking was increased and clearly observed in the coated tablets cured at 100°C for 24 hr. As a result, more water could be absorbed into the tablets, followed by faster disintegration and faster drug release. The evidence of partial conversion of chitosonium acetate to chitin in the ¹³C nuclear magnetic resonance (NMR) spectra of chitosan films cured at 40, 60, and 100°C was observed, but it had no effect on drug release behavior. Theophylline tablets coated with chitosan films gave sustained release behavior in various media, i.e., distilled water, 0.1 N hydrochloric acid, pH 4.5 acetate buffer, and pH 6.8 phosphate buffer. In addition, the film coating temperature at 55-60°C and curing process at 40 and 60°C had no effect on the drug release from theophylline tablets coated with chitosan polymer. Finally, it might be concluded that both the physical and chemical properties of chitosan films were affected by heat.     

Chitosan composite films. Biomedical applications

Chitosan acetate films have been prepared using chitosans from shrimps (Pleuroncodes monodon) of low and high molecular weight (LMv = 68,000 g/mol and HMv = 232,000 g/mol) and deacetylation degree of 80 and 100%, respectively. The chitosan films were obtained by addition of several additives to acetic acid chitosan solutions, such as: glycerol, oleic acid and linoleic acid in different proportions. The pH of the solutions before casting ranged from 5.0 to 6.0. The composite film thickness are reported. The films have been analyzed by FTIR showing characteristic bands corresponding to the additives. The scanning electron microscopy (SEM) studies reveals the different morphology of the composite films. The films exhibit different physical properties depending upon the additives and/or mixture of them. The addition of glycerol to composite improves the elasticity of the films. The swelling in glucose and saline solutions for several films was evaluated, being higher in the glucose solution. The bactericide test against Staphylococcus aureus, Pseudomona aeruginosa and Acinetobacter baumanii in plates with either blood and or agar tripticase showed that the molecular weight influences on the bactericidal properties of the chitosan composite films and over its effect against gram positive and gram negative bacteria. Medical applications of the composite films were done in patients with burns, ulcers and injuries, the films containing glycerol showed good adhesion in comparison with those without it. The composite films tested were mainly three (1) chitosan acetate with glycerol, (2) chitosan acetate with oleic acid and (3) chitosan acetate with glycerol and oleic acid. Excellent results in the skin recovery were obtained after 7–10 days. Since the chitosan is biodegradable by the body enzymes it does not need to be removed and increases the gradual grows of the damage tissues.     

Effect of anionic water-soluble dyes on film coating properties of chitosan acetate

Solution of chitosan in dilute acetic acid was prepared to have an apparent viscosity of 125 mPa s and mixed with solution of anionic water-soluble dye. The effects of concentration and type of dye and molecular weight and percentage deacetylation of chitosan on their miscibility and physical stability were investigated. High concentration of dye and high molecular weight and percentage deacetylation of chitosan resulted in precipitation or colloidal dispersion due to ionic interaction between dye and the polymer. The effect was more prominent upon storage. The miscibility of dye and the polymer depended on the molecular configuration and ionic group in the dye molecule. It was ranked brilliant blue approximately euqal to green FS > fast green > ponceau SX approximately euqal to green sunset yellow > erythrosine approximately euqal to green tartrazin > indigo carmine. Solutions of low molecular weight chitosan with and without green FS were then used as coating formulations onto propranolol hydrochloride core tablets. There was no color migration on coated tablets even after storage for 1 year. Disintegration and drug dissolution from tablets coated with colored film were slightly slower than those from tablets coated with plain film and core tablet, respectively. This was corresponding to the results of swelling and dissolution of cast films. However, all tablets conformed to the specification in monograph of USP XXIV.     

壳聚糖改性纤维素共混复合物的制备及性能

利于壳聚糖共混改性纤维素,介绍了共混改性复合物的制备方法,并利用红外光谱(FT-IR)、扫描电子显微(SEM)、x射线衍射(XRD)、热失重分析(TGA)、平衡水分含量及力学性能的测试对共混复合物的特征进行研究.结果表明,在共混复合物中纤维素和壳聚糖具有良好的相容性,没有相分离发生;共混壳聚糖后,随着壳聚糖含量的增加,...     

不同脱乙酰度壳聚糖制备及涂布纸包装性能研究

通过壳聚糖与乙酸酐发生N-乙酰化反应,制备了不同脱乙酰度的壳聚糖。利用傅里叶变化红外光谱(FTIR)及紫外光谱对产物进行了表征。将不同脱乙酰度壳聚糖在手抄纸上进行涂布,测试了涂布纸的力学性能及抗油脂性能。利用SEM分析了纸张增强及抗油脂作用机理。结果表明,乙酸酐与壳聚糖物质的量比在0.6以下时,脱乙酰度与乙酸酐加入量成线性关系;纸张的力学性能及抗油脂指数随涂布量增加而增加,当涂布量达到4.8 g/m2时,抗张指数提高了50.3%;相同涂布量下,随着脱乙酰度降低,抗张指数逐渐降低;当涂布量超过2.32 g/m2,抗油脂指数增长趋缓;壳聚糖的成膜微观结构对涂布纸的力学性能及抗油脂性能有重要影响。     

不同碳纳米管对壳聚糖膜性能的影响研究

目的研究普通碳纳米管(MWNT)与羧基化碳纳米管(MWNT-COOH)对壳聚糖复合膜性能的影响。方法将质量分数不同的MWNT与MWNT-COOH分别添加到壳聚糖基材中,采用溶液共混法制得纳米复合膜,并对复合膜的溶胀性能、透湿性能、力学性能、表面形貌和抑菌性能等进行表征。结果当MWNT和MWNT-COOH的质量分数均为1%时,2种复合膜的阻湿性能和拉伸性能相对于纯壳聚糖膜有明显改善,尤其是MWNT-COOH,2种碳纳米管的加入均可增强复合膜对大肠杆菌的抑制效果。结论浓度相同时,与MWNT相比,MWNT-COOH与壳聚糖间具有更强的结合力,它的加入能更有效地改善壳聚糖膜的性能。     

Design,characterization and ex vivo evaluation of chitosan film integrating of insulin nanoparticles composed of thiolated chitosan derivative for buccal delivery of insulin

The purpose of this study is to optimize and characterize of chitosan buccal film for delivery of insulin nanoparticles that were prepared from thiolated dimethyl ethyl chitosan (DMEC-Cys). Insulin nanoparticles composed of chitosan and dimethyl ethyl chitosan (DMEC) were also prepared as control groups. The release of insulin from nanoparticles was studied in vitro in phosphate buffer solution (PBS) pH 7.4. Optimization of chitosan buccal films has been carried out by central composite design (CCD) response surface methodology. Independent variables were different amounts of chitosan and glycerol as mucoadhesive polymer and plasticizer, respectively. Tensile strength and bioadhesion force were considered as dependent variables. Ex vivo study was performed on excised rabbit buccal mucosa. Optimized insulin nanoparticles were obtained with acceptable physicochemical properties. In vitro release profile of insulin nanoparticles revealed that the highest solubility of nanoparticles in aqueous media is related to DMEC-Cys nanoparticles. CCD showed that optimized buccal film containing 4% chitosan and 10% glycerol has 5.81?kg/mm² tensile strength and 2.47?N bioadhesion forces. Results of ex vivo study demonstrated that permeation of insulin nanoparticles through rabbit buccal mucosa is 17.1, 67.89 and 97.18% for chitosan, DMEC and DMEC-Cys nanoparticles, respectively. Thus, this study suggests that DMEC-Cys can act as a potential enhancer for buccal delivery of insulin.     

明胶-壳聚糖复合膜的制备与性能

制备了一系列不同配比的明胶-壳聚糖复合膜,研究了壳聚糖含量对复合膜力学性能、吸湿性能的影响,通过X射线衍射和红外光谱分析了复合膜的结构。结果表明,复合膜及纯壳聚糖膜的断裂伸长率和拉伸强度均大于纯明胶膜,壳聚糖的加入可改善膜的力学性能。随壳聚糖含量的增加,复合膜的吸湿率增大。明胶与壳聚糖分子间存在较强的相互作用,与明胶共...     

Degradability of kenaf dust-filled chitosan biocomposites

Degradability of environmentally friendly of kenaf dust-filled chitosan biocomposites was investigated. Biocomposites of chitosan/kenaf was prepared via solution blending method. Diluted acetic acid was used as solvent for dissolving the chitosan powder. High speed homogenizer was used to assist the dispersion of kenaf dust in chitosan solution. Five types of composites containing different amounts of kenaf dust; 0%, 7%, 14%, 21% and 28% were fabricated. Degradability of each composites were evaluated against seven different solutions; (0.1, 0.5, 1.0) M of H₂SO₄, (0.1, 0.5, 1.0) M of NaOH and distilled water. Degradation behaviors were evaluated based on percent of weight gain, percent of water absorption and degree of swelling. It was noted that, chitosan film which contains higher kenaf dust content showed greater stability against seven different solutions due to lower degree of swelling compared to chitosan film having lesser amount of kenaf dust. It was observed that the composites showed greater resistance towards alkaline and acidic solution as compared to distilled water.     

正交试验法研究淀粉-壳聚糖可食性包装膜的力学性能

采用溶液共混后流延的方法制备淀粉-壳聚糖可食性包装膜,运用正交试验法研究了壳聚糖质量分数、乙酸体积分数、淀粉质量分数、共混时间、甘油比例等因素对包装膜力学性能的影响。根据正交试验结果,壳聚糖质量分数、乙酸体积分数、甘油比例对包装膜的抗张强度和伸长率影响最为显著。当壳聚糖质量分数2%,乙酸体积分数6%,淀粉质量分数2%,共混时间10min,甘油质量比例35%时,共混膜的力学性能相对最优。     

负载桑葚花青素的葛根淀粉/壳聚糖复合膜的制备与表征

目的 研究桑葚花青素（Mulberry Anthocyanins, MA）添加量对葛根淀粉/壳聚糖复合膜理化性质及功能活性的影响。方法 以葛根淀粉和壳聚糖为成膜基材，MA为指示剂，采用流延法制备一种新型可食pH指示膜，测定葛根淀粉/壳聚糖复合膜的物理性能、抗氧化性、pH指示等性质，并将指示膜用于猪肉保鲜及新鲜度检测研究。结果 通过对添加不同MA含量的复合膜进行性能测试，发现MA和葛根淀粉之间氢键的形成，极大地改善了复合膜的拉伸强度。MA的加入使得成膜厚度、不透明度、拉伸强度（Tensile Strength,TS）、水蒸气透过率（Water Vapor Permeability,WVP）显著提高，断裂伸长率（Elongation At Break,EAB）显著降低。此外，MA增强了复合膜的抗氧化性和pH敏感性，MA-4的DPPH自由基清除率达到最大值85.24%。将复合膜应用于猪肉新鲜度检测，与对照组相比，负载MA的复合膜可抑制猪肉pH值和TVB-N值，并产生肉眼可辨的颜色变化，其中MA-3的颜色变化最为敏感。结论 加入一定量MA的复合膜能够改善其拉伸强度、不透明度、pH敏感性和抗氧化...     

Synthesis of water-soluble urethane acrylate anionomers and their ultra-violet coating properties

Water-soluble and ultraviolet (UV)-curable urethane acrylate anionomers containing dimethylolpropionic acid (DMPA) were synthesized with varying molecular weight of soft segment and degree of neutralization. The ion group incorporated was confirmed by ¹H-NMR and ¹³C-NMR spectra. In viscosity measurements, the enhancement of viscosity was achieved with increasing of ionic strength or pH of the solution. However, when the molecular weight of soft segment was high, the viscosity little changed for given parameters. This indicates that the strong hydrophobic interaction caused by the long soft segment made the anionomer chain aggregate. The UV coating properties of urethane acrylate anionomer films were depended on the molecular weight of soft segment and the degree of neutralization. For the films of high ion content and low molecular weight of soft segment, the tensile strength had a tendency toward increasing, on the contrary, for the films of low ion content and high molecular weight of soft segment, the tensile strength displayed reverse tendency. However, compared with general urethane acrylate films, overall coating properties were significantly improved. This was believed that the ionic groups acted as reinforcing filler by means of the phase separation from the crosslinked urethane acrylate network.     

Chitosan and Sodium Sulfate as Excipients in the Preparation of Prolonged Release Theophylline Tablets

The major objectives of this study were to monitor the effect of cross-linking of cationic chitosan in acidic media with sulfate anion during granules preparation by wet granulation method prior to tableting using theophylline (TPH) as a model drug. The prepared granules and the compressed tablets were subjected to in vitro evaluation. The properties of the prepared matrix granules and the compressed tablets were dependent on chitosan:sodium sulfate weight ratios, chitosan content, and molecular weight of chitosan. The prepared granules of all batches showed excellent to passable flowability and were suitable for compression into tablets. Most of the granules were hard and expected to withstand handling during the subsequent compression into tablets. Granules with high friabilities were only those prepared with a high amount of sodium sulfate or low amount of chitosan. Compression of granule batches yield nondisintegrating tablets that showed a decrease in tensile strength with the increase of sodium sulfate content at high chitosan:sodium sulfate weight ratio or with decrease of chitosan content. On the other hand, friability of tablets was increased in the presence of an excessive amount of sodium sulfate and low chitosan content as observed with granules. Slow TPH release from the formulated tablets was achieved at 1:0.5 and 1:1 chitosan:sodium sulfate weight ratios where all or most of the cationic chitosan and sulfate anions were used in a cross-linking reaction during wet granulation. Ratios of 1:2 and 1:3 showed fast drug release, which support the hypothesis that excessive unreacted water-soluble sodium sulfate might increase the porosity of the nondesintegrating tablets during dissolution. Slow drug release was also obtained with high molecular weight chitosan, whereas changing the hardness of the tablets did not significantly change the release profile of the drug as long as the tablets are intact during dissolution. Furthermore, slow drug release was observed as the total amount of chitosan was increased in the formulated tablets. A comparative in vivo study between the chosen formulated tablets (1:1 chitosan:sodium sulfate ratio that contains 10% high molecular weight chitosan) and the commercial Quibron® tablets indicated prolonged appearance of the drug in dogs' plasma for both formulations with no significant differences (p > 0.05) in rate and extent of drug absorption. The formulated tablets showed 103.16% bioavailability relative to that of the commercial tablets.     

Chitosan and sodium sulfate as excipients in the preparation of prolonged release theophylline tablets

The major objectives of this study were to monitor the effect of cross-linking of cationic chitosan in acidic media with sulfate anion during granules preparation by wet granulation method prior to tableting using theophylline (TPH) as a model drug. The prepared granules and the compressed tablets were subjected to in vitro evaluation. The properties of the prepared matrix granules and the compressed tablets were dependent on chitosan:sodium sulfate weight ratios, chitosan content, and molecular weight of chitosan. The prepared granules of all batches showed excellent to passable flowability and were suitable for compression into tablets. Most of the granules were hard and expected to withstand handling during the subsequent compression into tablets. Granules with high friabilities were only those prepared with a high amount of sodium sulfate or low amount of chitosan. Compression of granule batches yield nondisintegrating tablets that showed a decrease in tensile strength with the increase of sodium sulfate content at high chitosan:sodium sulfate weight ratio or with decrease of chitosan content. On the other hand, friability of tablets was increased in the presence of an excessive amount of sodium sulfate and low chitosan content as observed with granules. Slow TPH release from the formulated tablets was achieved at 1:0.5 and 1:1 chitosan:sodium sulfate weight ratios where all or most of the cationic chitosan and sulfate anions were used in a cross-linking reaction during wet granulation. Ratios of 1:2 and 1:3 showed fast drug release, which support the hypothesis that excessive unreacted water-soluble sodium sulfate might increase the porosity of the nondesintegrating tablets during dissolution. Slow drug release was also obtained with high molecular weight chitosan, whereas changing the hardness of the tablets did not significantly change the release profile of the drug as long as the tablets are intact during dissolution. Furthermore, slow drug release was observed as the total amount of chitosan was increased in the formulated tablets. A comparative in vivo study between the chosen formulated tablets (1:1 chitosan:sodium sulfate ratio that contains 10% high molecular weight chitosan) and the commercial Quibron tablets indicated prolonged appearance of the drug in dogs' plasma for both formulations with no significant differences (p > 0.05) in rate and extent of drug absorption. The formulated tablets showed 103.16% bioavailability relative to that of the commercial tablets.     

小麦醇溶蛋白膜力学性能与吸湿性研究

采用小麦醇溶蛋白的乙醇/水(70/30(v/v))溶液制备了醇溶蛋白膜,分析了交联剂用量与pH值对膜的拉伸性能、吸水性及透湿性的影响.结果表明,适度交联的醇溶蛋白膜具有最大拉伸强度与较高的断裂伸长率.随交联剂用量增加,膜的吸水率稍有下降,而透湿性显著增大.酸碱处理能显著提高膜的拉伸强度,但使吸水性稍有增大.     

戊二醛改性壳聚糖/ 纳米TiO2 复合膜的抗水性研究

采用戊二醛作为交联剂与壳聚糖进行交联,以提高壳聚糖/ 纳米TiO2 膜的抗水性。采用三元二次通用旋转组合设计实验方法,建立了力学性能、吸水率与戊二醛用量、交联时间、TiO2 溶胶添加量的二次回归数学模型,得出了制备戊二醛改性壳聚糖/ 纳米TiO2 膜的最佳工艺条件为交联剂用量0. 10 g/ (100 mL)乙酸溶液,交联时间4. 37 h,TiO2 溶胶添加量0. 08 mL/ (100 mL)的乙酸溶液。上述条件下得到的膜的拉伸强度为5. 69MPa,吸水率为133. 66%。与壳聚糖/ 纳米TiO2 膜相比,吸水率下降了72. 8%。     

Synthesis and characterization of carboxymethyl chitosan hydrogel: Application as site specific delivery for lercanidipine hydrochloride

In the present study, carboxymethylchitosan (CMCS) was prepared from chitosan, crosslinked with glutaraldehyde and evaluated in vitro as a potential carrier for site specific drug delivery of lercanidipine hydrochloride (LERH). LERH was incorporated at the time of crosslinking of CMCS. The chitosan was evaluated for its degree of deacetylation (DD) and average molecular weight, which were found to be 84·6% and 3·5 × 10⁴ Da, respectively. The degree of substitution on prepared CMCS was found to be 0·68. All hydrogel formulations showed more than 86% and 77% yield and drug loading, respectively. The swelling behaviour of prepared hydrogels were checked in different pH values, 1·2, 6·8 and 7·4, indicated pH responsive swelling characteristic with very less swelling at pH 1·2 and quick swelling at pH 6·8 followed by linear swelling at pH 7·4 with slight increase. In vitro release profile was carried out at the same conditions as in swelling and drug release was found to be dependent on swelling of hydrogels and showed biphasic release pattern with non-fickian diffusion kinetics at higher pH. The carboxymethylation of chitosan, entrapment of drug and its interaction in prepared hydrogels were checked by FTIR, ¹H-NMR, DSC and p-XRD studies, which confirmed formation of CMCS from chitosan and absence of any significant chemical change in LERH after being entrapped in crosslinked hydrogel formulations. The surface morphology of formulation S6 was checked before and after dissolution, revealed open channel like pores formation after dissolution.     

Development of chitosan/gelatin/keratin composite containing hydrocortisone sodium succinate as a buccal mucoadhesive patch to treat desquamative gingivitis

The aim of this research was to develop chitosan/gelatin/keratin composite containing hydrocortisone sodium succinate as a buccal mucoadhesive patch to treat desquamative gingivitis, which was fabricated through an environmental friendly process. Mucoadhesive films increase the advantage of higher efficiency and drug localization in the affected region. In this research, mucoadhesive films, for the release of hydrocortisone sodium succinate, were prepared using different ratios of chitosan, gelatin and keratin. In the first step, chitosan and gelatin proportions were optimized after evaluating the mechanical properties, swelling capacity, water uptake, stability, and biodegradation of the films. Then, keratin was added at different percentages to the optimum composite of chitosan and gelatin together with the drug. The results of surface pH showed that none of the samples were harmful to the buccal cavity. FTIR analysis confirmed the influence of keratin on the structure of the composite. The presence of a higher amount of keratin in the composite films resulted in high mechanical, mucoadhesive properties and stability, low water uptake and biodegradation in phosphate buffer saline (pH?=?7.4) containing 10⁴?U/ml lysozyme. The release profile of the films ascertained that keratin is a rate controller in the release of the hydrocortisone sodium succinate. Finally, chitosan/gelatin/keratin composite containing hydrocortisone sodium succinate can be employed in dental applications.     

壳聚糖/纳米TiO2杂化材料的制备及抗菌性能表征

制备了壳聚糖/纳米TiO2杂化膜,表征了其抗菌性能,分析了影响TiO2纳米粒子在壳聚糖溶液中分散性的影响因素。FT-IR、AFM分析了杂化膜的结构与形态。表明促进TiO2颗粒良好分散有四个主要因素:(1)表面电荷的重新分布;(2)空间保护作用;(3)化学键的相互作用;(4)超声分散。抗菌实验表明壳聚糖/纳米TiO2杂化膜具有很强的抗菌性能,细菌的形态学变化具有两个显著的特点:(1)细胞内物质渗漏,在细胞周围形成了环状结构;(2)细胞表面囊泡的形成。