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Chitosan
Kinds of Chitosan Terms modified by Chitosan Selected AbstractsANTIMICROBIAL, PHYSICAL AND MECHANICAL PROPERTIES OF CHITOSAN-BASED FILMS INCORPORATED WITH THYME, CLOVE AND CINNAMON ESSENTIAL OILSJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 6 2009M.H. HOSSEINI ABSTRACT Chitosan-based films containing thyme, clove and cinnamon essential oils at 0.5, 1 and 1.5% v/v were prepared to examine their antibacterial, physical and mechanical properties. Scanning electron microscopy was carried out to explain structure,property relationships. Films containing thyme essential oil revealed larger inhibition zones than those containing clove and cinnamon essential oils against gram-positive and gram-negative bacteria tested. Films were more effective against gram-positive bacteria than gram-negative. Incorporating thyme and clove essential oils into chitosan-based films increased moisture content (from 17.80,28.38%), solubility in water (25.97,30.62%), water vapor transmission rate (0.00233,0.00571 g/s/m2) and elongation at break (25.31,42.70%) of films. Cinnamon-enriched films had opposite changes such as increase in tensile strength (from 12.2,21.35 MPa) and decrease in moisture content (17.80,9.36%) and solubility in water (25.9,14.21%) of films. PRACTICAL APPLICATIONS Microbial growth on food surfaces is a major cause of food spoilage. Combining antimicrobial agents such as plant essential oils directly into a food packaging polymer is a form of active packaging. These films possess the potential for improving microbial stability of foods by acting on the food surface upon contact. Because of the effect of direct addition of plant essential oils to food on sensory characteristics of packaged food, incorporation of essential oils into films may have additional applications in food packaging. [source] Multilayer Assembly of Hemoglobin and Colloidal Gold Nanoparticles on Multiwall Carbon Nanotubes/Chitosan Composite for Detecting Hydrogen PeroxideELECTROANALYSIS, Issue 19 2008Shihong Chen Abstract Chitosan (CS) was chosen for dispersing multi-wall carbon nanotubes (MWNTs) to form a stable CS-MWNTs composite, which was first coated on the surface of a glassy carbon electrode to provide a containing amino groups interface for assembling colloidal gold nanoparticles (GNPs), followed by the adsorption of hemoglobin (Hb). Repeating the assembly step of GNPs and Hb resulted in {Hb/GNPs}n multilayers. The assembly of GNPs onto CS-MWNTs composites was confirmed by transmission electron microscopy. The consecutive growth of {Hb/GNPs}n multilayers was confirmed by cyclic voltammetry and UV-vis absorption spectroscopy. The resulting system brings a new platform for electrochemical devices by using the synergistic action of the electrocatalytic activity of GNPs and MWNTs. The resulting biosensor displays an excellent electrocatalytic activity and rapid response for hydrogen peroxide. The linear range for the determination of H2O2 was from 5.0×10,7 to 2.0×10,3 M with a detection limit of 2.1×10,7 M at 3, and a Michaelis,Menten constant KMapp value of 0.19,mM. [source] Electrooxidation of DNA at Glassy Carbon Electrodes Modified with Multiwall Carbon Nanotubes Dispersed in ChitosanELECTROANALYSIS, Issue 7-8 2007Soledad Bollo Abstract We report on the analytical performance of glassy carbon (GCE) electrodes modified with a dispersion of multiwall carbon nanotubes (CNT) in chitosan (CHIT) for the quantification of DNA. The electroanalytical response of the resulting electrodes was evaluated using differential pulse voltammetry, while the electrochemical reactivity of the film surface was characterized using scanning electrochemical microscopy. Different treatments of the modified GCE were evaluated to improve the stability of the film and the accumulation of DNA. The guanine oxidation signal of double stranded calf-thymus DNA after 3-min accumulation was 20 times higher at GCE/CHIT-CNT cross-linked with glutaraldehyde (GTA) than at bare GCE, while the peak potential was around 45,mV less positive. The guanine oxidation signal demonstrated to be highly reproducible, with 3.4% RSD for 5 different electrodes. The treatment with sodium hydroxide demonstrated to be not effective since the resulting films were less stable and the guanine oxidation signal was ten times smaller compared to electrodes prepared with the GTA treated films. The effect of chitosan molecular weight used to prepare the dispersion and the amount of carbon nanotubes dispersed were evaluated. The response of single stranded DNA and oligo(dG)15 is also discussed. [source] Development of Biomimetic Chitosan-Based Hydrogels Using an Elastin-Like Polymer,ADVANCED ENGINEERING MATERIALS, Issue 1-2 2010Joaquim S. Barbosa Chitosan and an elastin-like polymer, containing a specific osteoconductive sequence in the primary structure, have been combined to obtain bioactive injectable systems with enhanced mechanical properties and hydrogels. Obtained results indicate that the combination of such polymers may be very promising in the development of biomaterials for minimal invasive orthopaedic reconstructive applications or in bone tissue engineering. The figure shows a thermo-sensitive hydrogel, with a gelation point under physiological temperature. [source] A Short-Term Bioresorbable Bone Filling Material Based on Hydroxyapatite, Chitosan, and Oxidized Starch Tested in a Novel Orthotopic Metaphyseal Mouse Model,ADVANCED ENGINEERING MATERIALS, Issue 8 2009Elias Volkmer Despite significant advances in orthopedic surgery, no perfect bioresorbable bone-filling material has yet been clinically established. A new candidate material based on hydroxyapatite, chitosan and oxidised starch, which has the potential to covalently bind to bone in a watery milieu was tested in a new murine model. A special focus lies on the in vivo biocompatibility and bioresorbability of the new material. [source] Functionalization of Chitosan via Atom Transfer Radical Polymerization for Gene DeliveryADVANCED FUNCTIONAL MATERIALS, Issue 18 2010Yuan Ping Abstract It is of crucial importance to modify chitosan-based polysaccharides in the designing of biomedical materials. In this work, atom transfer radical polymerization (ATRP) was employed to functionalize chitosan in a well-controlled manner. A series of new degradable cationic polymers (termed as PDCS) composed of biocompatible chitosan backbones and poly((2-dimethyl amino)ethyl methacrylate) (P(DMAEMA)) side chains of different length were designed as highly efficient gene vectors via ATRP. These vectors, termed as PDCS, exhibited good ability to condense plasmid DNA (pDNA) into nanoparticles with positive charge at nitrogen/phosphorus (N/P) ratios of 4 or higher. All PDCS vectors could well protect the condensed DNA from enzymatic degradation by DNase I and they displayed high level of transfectivity in both COS7, HEK293 and HepG2 cell lines. Most importantly, in comparison with high-molecular-weight P(DMAEMA) and ,gold-standard' PEI (25 kDa), the PDCS vectors showed considerable buffering capacity in the pH range of 7.4 to 5, and were capable of mediating much more efficient gene transfection at low N/P ratios. At their own optimal N/P ratios for trasnsfection, the PDCS/pDNA complexes showed much lower cytotoxicity. All the PDCS vectors were readily to be degradable in the presence of lysozyme at physiological conditions in vitro. These well-defined PDCS polymers have great potentials as efficient gene vectors in future gene therapy. [source] Chitosan per os: from Dietary Supplement to Drug CarrierFOCUS ON ALTERNATIVE AND COMPLEMENTARY THERAPIES AN EVIDENCE-BASED APPROACH, Issue 3 2000MH Pittler [source] Controlled Degradability of Polysaccharide Multilayer Films In Vitro and In Vivo,ADVANCED FUNCTIONAL MATERIALS, Issue 11 2005C. Picart Abstract This article demonstrates the possibility of tuning the degradability of polysaccharide multilayer films in vitro and in vivo. Chitosan and hyaluronan multilayer films (CHI/HA) were either native or crosslinked using a water soluble carbodiimide, 1-ethyl-3-(3-dimethylamino-propyl)carbodiimide (EDC) at various concentrations in combination with N-hydroxysulfosuccinimide. The in-vitro degradation of the films in contact with lysozyme and hyaluronidase was followed by quartz crystal microbalance measurements, fluorimetry, and confocal laser scanning microscopy after labeling of the chitosan with fluorescein isothiocyanate (CHIFITC). The native films were subjected to degradation by these enzymes, and the crosslinked films were more resistant to enzymatic degradation. Films made of chitosan of medium molecular weight were more resistant than films made of chitosan-oligosaccharides. The films were also brought in contact with plasma, which induced a change in film structure for the native film but did not have any effect on the crosslinked film. The in-vitro study shows that macrophages can degrade all types of films and internalize the chitosan. The in-vivo degradation of the films implanted in mouse peritoneal cavity for a week again showed an almost complete degradation of the native films, whereas the crosslinked films were only partially degraded. Taken together, these results suggest that polysaccharide multilayer films are of potential interest for in-vivo applications as biodegradable coatings, and that degradation can be tuned by using chitosan of different molecular weights and by controlling film crosslinking. [source] 2-Azido-2-deoxycellulose: Synthesis and 1,3-Dipolar CycloadditionHELVETICA CHIMICA ACTA, Issue 4 2008Fuyi Zhang Abstract Chitosan (1) was prepared by basic hydrolysis of chitin of an average molecular weight of 70000 Da, 1H-NMR spectra indicating almost complete deacetylation. N -Phthaloylation of 1 yielded the known N -phthaloylchitosan (2), which was tritylated to provide 3a and methoxytritylated to 3b. Dephthaloylation of 3a with NH2NH2,H2O gave the 6- O -tritylated chitosan 4a. Similarly, 3b gave the 6- O -methoxytritylated 4b. CuSO4 -Catalyzed diazo transfer to 4a yielded 95% of the azide 5a, and uncatalyzed diazo transfer to 4b gave 82% of azide 5b. Further treatment of 5a with CuSO4 produced 2-azido-2-deoxycellulose (7). Demethoxytritylation of 5b in HCOOH gave 2-azido-2-deoxy-3,6-di- O -formylcellulose (6), which was deformylated to 7. The 1,3-dipolar cycloaddition of 7 to a range of phenyl-, (phenyl)alkyl-, and alkyl-monosubstituted alkynes in DMSO in the presence of CuI gave the 1,2,3-triazoles 8,15 in high yields. [source] Entering and Lighting Up Nuclei Using Hollow Chitosan,Gold Hybrid NanospheresADVANCED MATERIALS, Issue 36 2009Yong Hu Functional hollow CS,PAA,Au-hybrid nanospheres are prepared in aqueous solution via a one-pot route. These hollow hybrid nanospheres can not only act as drug carriers for intracellular and intranuclear drug delivery, but also act as a contrast agent in cancer-cell imaging, and light up the nucleus. This results in a nanosphere that can execute tumor-cell imaging and anticancer drug delivery at the same time. [source] Chitosan-Based Inverse Opals: Three-Dimensional Scaffolds with Uniform Pore Structures for Cell CultureADVANCED MATERIALS, Issue 29 2009Sung-Wook Choi Chitosan inverse opal scaffolds: Three-dimensional chitosan scaffolds with an inverse opal structure have been fabricated using a cubic close packed lattice of polymer beads as the template. The scaffolds have a uniform and interconnected pore structure as well as a fibrous morphology on the wall. They can be used as a model system for in vitro studies of cell culture and as clinically practical scaffolds for tissue engineering. [source] Importance of the Conditioning of the Chitosan Support in a Catalyst-Containing Ionic Liquid Phase Immobilised on Chitosan: The Palladium-Catalysed Allylation Reaction CaseADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2010Renaud Moucel No abstract is available for this article. [source] Importance of the Conditioning of the Chitosan Support in a Catalyst-Containing Ionic Liquid Phase Immobilised on Chitosan: The Palladium-Catalysed Allylation Reaction CaseADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010Renaud Moucel Abstract Catalysts containing ionic liquid phase immobilised on chitosan are successfully applied to the palladium-catalysed allylation reaction. A strong influence of the conditioning of chitosan not only on the activity and enantioselectivity but also on the recyclability and reusability of the catalyst is demonstrated. [source] Preparation of monomethyl poly(ethylene glycol)- g -chitosan copolymers with various degrees of substitution: Their ability to encapsulate and condense plasmid DNAJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008Wei Zhang Abstract Chitosan (CS) has great potential as a nonvirus gene delivery vector, but its application is limited because of poor water solubility. Monomethyl poly(ethylene glycol) (mPEG)- graft -CS copolymers were synthesized by the reaction of mPEG,aldehyde (oxidized mPEG) with amino groups on CS chains; they showed enhanced solubility in water. Copolymers with various mPEG degrees of substitution (DS) and CS molecular weights were obtained, and their capabilities of DNA encapsulation were compared through gel retardation assay and particle size and , potential measurements. The effects of different ratios of primary amines on CS to the phosphate groups on DNA (N/P ratios), DS, and molecular weights on particle size and encapsulation efficiency were investigated. The results show that high N/P ratios and proper DS were necessary for the formation of well-distributed complex particles. Among all of these samples, mPEG (3.55),CS (50 kDa)/DNA complexes [where the parentheses following mPEG indicate DS (%), and the parentheses following CS indicate the molecular weight of CS] raised the , potential from negative to positive most quickly, yielded the smallest particle size, and were retarded in agarose gel at the lowest N/P ratio; this indicated the best efficiency of DNA encapsulation. On the contrary, mPEG (0.80),CS (50 kDa)/DNA complexes raised the , potential to positive most slowly, fluctuated around the value 0 from N/P ratios of 15 : 1 to 30 : 1, and were retarded in agarose gel at the highest N/P ratio; this indicated the lowest efficiency of encapsulating plasmids. Copolymers with desirable efficiencies of DNA encapsulation could be promising gene carriers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Preparation and adsorption properties of chitosan,poly(acrylic acid) nanoparticles for the removal of nickel ionsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2008Jian-Wen Wang Abstract Chitosan (CS) nanoparticles with different mean sizes ranging from 100 to 195 nm were prepared by ionic gelation of CS and poly(acrylic acid) (PAA). Variations in the final solution pH value and CS : PAA volume ratio were examined systematically for their effects on nanoparticle size, intensity of surface charge, and tendency toward particle aggregation. The sorption capacity and sorption isotherms of the CS,PAA nanoparticles for nickel ions were evaluated. The parameters for the adsorption of nickel ions by the CS,PAA nanoparticles were also investigated. The CS,PAA nanoparticles could sorb nickel ions effectively. The sorption rate for nickel ions was affected significantly by the initial concentration of the solution, sorbent amount, particle size, and pH value of the solution. The samples of nanoparticles were well correlated with Langmuir's isotherm model, and the adsorption kinetics of nickel correlated well with the pseudo-second-order model. The maximum capacity for nickel sorption deduced from the use of the Langmuir isotherm equation was 435 mg/g, which was significantly higher than that of the micrometer-sized CS. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 [source] Chitosan-based interpolymeric pH-responsive hydrogels for in vitro drug releaseJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2007M. Y. Abdelaal Abstract Two series of pH-responsive biodegradable interpolymeric (IPN) hydrogels based on chitosan (Ch) and poly(vinyl alcohol) (PVA) were prepared for controlled drug release investigations. The first series was chemically crosslinked with different concentrations of glutaraldehyde and the second was crosslinked upon ,-irradiation by different doses. The equilibrium swelling characteristics were investigated for the gels at 37°C in buffer solutions of pH 2.1 and 7.4 as simulated gastric and intestinal fluids, respectively. 5-Fluorouracil (FU) was entrapped in the hydrogels, as a model therapeutic agent, and the in vitro release profiles of the drug were established at 37°C in pH 2.1 and 7.4. FTIR, SEM, and X-ray diffraction analyses were used to characterize and investigate the structural changes of the gels with the variation of the blend composition and crosslinker content before and after the drug loading. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2864,2874, 2007 [source] THE DEGRADATION OF CHlTOSAN WITH THE AID OF LIPASE FROM RHIZOPUS JAPONICUS FOR THE PRODUCTION OF SOLUBLE CHlTOSANJOURNAL OF FOOD BIOCHEMISTRY, Issue 4 2001SEUNG S. SHIN ABSTRACT Lipase from Rhizopus japonicus degraded chitosan resulting in soluble chitosan hydrolysates with molecular weight of about 30,50 kDa as shown by size exclusion chromatography. Optimal temperature for the hydrolysis of chitosan was 40C. The chitosan degradation products were fractionated stepwise according to their molecular weights by ultrafiltration with the filtration range of over 0.1 ,m, 0. l ,m to 30 kDa, 30 kDa to 10 kDa, 10 to 3 kDa, and 3 to 0.2 kDa. These fractions exhibited molecular weights of 50, 41, 41, 35, and 30 kDa, respectively. The molecular weights did not coincide with the pore size of filter membranes. Chitosan hydrolysate exhibited almost the same structural composition in IR spectra as chitosan flakes, except the peak of 1550 nm,1 that appeared to be the COO residue shifted from sodium acetate buffer to amine residue of chitosan. All fractions showed high solubility at neutral pH. The chitosan hydrolysates exhibiting molecular weights between 30 and 41 kDa were considered to be most suitable as a food additive or functional agent as demonstrated by sensory evaluation. [source] ANTIMICROBIAL, PHYSICAL AND MECHANICAL PROPERTIES OF CHITOSAN-BASED FILMS INCORPORATED WITH THYME, CLOVE AND CINNAMON ESSENTIAL OILSJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 6 2009M.H. HOSSEINI ABSTRACT Chitosan-based films containing thyme, clove and cinnamon essential oils at 0.5, 1 and 1.5% v/v were prepared to examine their antibacterial, physical and mechanical properties. Scanning electron microscopy was carried out to explain structure,property relationships. Films containing thyme essential oil revealed larger inhibition zones than those containing clove and cinnamon essential oils against gram-positive and gram-negative bacteria tested. Films were more effective against gram-positive bacteria than gram-negative. Incorporating thyme and clove essential oils into chitosan-based films increased moisture content (from 17.80,28.38%), solubility in water (25.97,30.62%), water vapor transmission rate (0.00233,0.00571 g/s/m2) and elongation at break (25.31,42.70%) of films. Cinnamon-enriched films had opposite changes such as increase in tensile strength (from 12.2,21.35 MPa) and decrease in moisture content (17.80,9.36%) and solubility in water (25.9,14.21%) of films. PRACTICAL APPLICATIONS Microbial growth on food surfaces is a major cause of food spoilage. Combining antimicrobial agents such as plant essential oils directly into a food packaging polymer is a form of active packaging. These films possess the potential for improving microbial stability of foods by acting on the food surface upon contact. Because of the effect of direct addition of plant essential oils to food on sensory characteristics of packaged food, incorporation of essential oils into films may have additional applications in food packaging. [source] Inactivation of Escherichia coli K-12 in Apple Juice Using Combination of High-Pressure Homogenization and ChitosanJOURNAL OF FOOD SCIENCE, Issue 1 2009S. Kumar ABSTRACT:, Apple juice and apple cider were inoculated with Escherichia coli K-12 and processed using a high-pressure homogenizer to study bacterial inactivation. Seven levels of pressure ranging from 50 to 350 MPa were used in the high-pressure homogenizer. Two types of chitosan (regular and water soluble) with 2 levels of concentration 0.01% and 0.1% were investigated for synergistic effect with high-pressure homogenization for the bacterial inactivation. E. coli K-12 inactivation was evaluated as a function of homogenizing pressure at different concentration of 2 types of chitosan in apple juice and cider. High-pressure homogenization (HPH) induced significant inactivation in the range of 100 to 200 MPa, while thermal inactivation was the primary factor for the bacterial inactivation above 250 MPa. Significant (P < 0.05) 2-way interactions involving pressure and type of substrate or pressure and chitosan concentration were observed during the study. The homogenization pressure and the incremental quantity of chitosan (both types) acted synergistically with the pressure to give higher inactivation. Significantly (P < 0.05) higher inactivation was observed in apple juice than apple cider at same homogenizing pressure. No effect of type of chitosan was observed on the bacterial inactivation. [source] Chitosan Protects Cooked Ground Beef and Turkey Against Clostridium perfringens Spores During ChillingJOURNAL OF FOOD SCIENCE, Issue 6 2006Vijay K. Juneja ABSTRACT:, We investigated the inhibition of Clostridium perfringens spore germination and outgrowth by the biopolymer chitosan during abusive chilling of cooked ground beef (25% fat) and turkey (7% fat) obtained from a retail store. Chitosan was mixed into the thawed beef or turkey at concentrations of 0.5%, 1.0%, 2.0%, or 3.0% (w/w) along with a heat-activated 3-strain spore cocktail to obtain a final spore concentration of 2 to 3 log10 CFU/g. Samples (5 g) of the ground beef or turkey mixtures were then vacuum-packaged and cooked to 60 °C in 1 h in a temperature-controlled water bath. Thereafter, the products were cooled from 54.4 to 7.2 °C in 12, 15, 18, or 21 h, resulting in 4.21, 4.51, 5.03, and 4.70 log10 CFU/g increases, respectively, in C. perfringens populations in the ground beef control samples without chitosan. The corresponding increases for ground turkey were 5.27, 4.52, 5.11, and 5.38 log10 CFU/g. Addition of chitosan to beef or turkey resulted in concentration- and time-dependent inhibition in the C. perfringens spore germination and outgrowth. At 3%, chitosan reduced by 4 to 5 log10 CFU/g C. perfringens spore germination and outgrowth (P, 0.05) during exponential cooling of the cooked beef or turkey in 12, 15, or 18 h. The reduction was significantly lower (P < 0.05) at a chilling time of 21 h, about 2 log10 CFU/g, that is, 7.56 log10 CFU/g (unsupplemented) compared with 5.59 log10 CFU/g (3% chitosan). The results suggest that incorporation of 3% chitosan into ground beef or turkey may reduce the potential risk of C. perfringens spore germination and outgrowth during abusive cooling from 54.4 to 7.2 °C in 12, 15, or 18 h. [source] Effect of Plasticizer Concentration and Solvent Types on Shelf-life of Eggs Coated with ChitosanJOURNAL OF FOOD SCIENCE, Issue 4 2006Su Hyun Kim ABSTRACT:, Effects of plasticizer concentrations (0, 0.5, 1.0, 1.5, and 2.0% glycerol) and solvent types (1% acetic and 1% lactic acid) on internal quality of eggs coated with 2% chitosan solution were evaluated during 5 wk of storage at 25 °C. In comparison of plasticizer concentrations, eggs coated with chitosan dissolved in acetic acid containing 2% glycerol showed significant reduction in weight loss compared with the noncoated eggs during 5 wk of storage. At 2% glycerol, the Haugh unit and yolk index values suggested that chitosan-coated eggs can be preserved for at least 3 wk longer than the control noncoated eggs during 5 wk of storage at 25 °C. Use of acetic acid rather than lactic acid as a chitosan solvent was more advantageous in view of shelf-life extension of eggs. [source] Enhancing Physical Properties and Antimicrobial Activity of Konjac Glucomannan Edible Films by Incorporating Chitosan and NisinJOURNAL OF FOOD SCIENCE, Issue 3 2006Bin Li ABSTRACT: The antimicrobial effect of konjac glucomannan (KGM) edible űlm incorporating chitosan (CHI) and nisin at various ratios or concentrations was studied. This activity was tested against pathogenic bacteria, namely, Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, and Bacillus cereus. Mechanical and physical properties were determined, and the results indicated that the blend film KC2 (mixing ratio KGM 80/ CHI 20) showed the maximum tensile strength (102.8 ± 3.8 MPa) and good transparency, water solubility, and water vapor transmission ratio. Differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the structural change of the blend films; and the results showed that strong intermolecular hydrogen bonds occurred between CHI and KGM. Incorporation of nisin at 463IU per disk of film for the selected KC2 was found to have antimicrobial activity against S. aureus, L. monocytogenes, and B. cereus. The mean value of inhibition zone diameter of the CHI-N series and the KC2-N series were higher than the KGM-N series at each corresponding concentration and with significant difference (P < 0.05), however, there was no significant difference in the antimicrobial effect between CHI and KC2 incorporating nisin. At all these levels, the blend űlm KC2-nisin had a satisfactory appearance, mechanical and physical properties, and antimicrobial activity. Therefore, it could be considered as a potential "active" packaging material. [source] Development of Shelf-stable Intermediate-moisture Meat Products Using Active Edible ChitosanCoating and IrradiationJOURNAL OF FOOD SCIENCE, Issue 7 2005M. Shobita Rao ABSTRACT Shelf-stable intermediate-moisture (IM) meat products were developed using a combination of hurdles such as reduced aw, active edible coating of chitosan, and irradiation. Chitosan prepared from chitin had a viscosity of 16 c P, molecular weight of 17.54 kDa, and a degree of deacetylation (DD) of 74%. The nitrogen content of the chitosan was estimated to be 7.56%. The antioxidant activity of chitosan increased upon irradiation without significantly affecting its antimicrobial property. The effect of irradiated chitosan coating in terms of its antimicrobial and antioxidant properties in IM meat products immediately after irradiation and during storage was assessed. The aw of meat products such as mutton sheek kababs and streaky bacon was first reduced to 0.85 ± 0.02. The products were then coated with chitosan and irradiated (4 kGy). No viable bacteria or fungi were detected in chitosan-coated, irradiated products. In contrast, IM meat products that were not subjected to gamma radiation showed visible fungal growth within 2 wk. The chitosan-coated products showed lower thiobarbituric acid-reactive substances (TBARS) than the noncoated samples for up to 4 wk of storage at ambient temperature. The studies thus clearly indicated the potential use of chitosan coating for the preparation of safe and stable meat products. [source] Chitosan(chitin)/cellulose composite biosorbents prepared using ionic liquid for heavy metal ions adsorptionAICHE JOURNAL, Issue 8 2009Xiaoqi Sun Abstract Chitosan(chitin)/cellulose composites as biodegradable biosorbents were prepared under an environment-friendly preparation processes using ionic liquids. Infrared and X-ray photoelectron spectra indicated the stronger intermolecular hydrogen bond between chitosan and cellulose, and the hydroxyl and amine groups were believed to be the metal ion binding sites. Among the prepared biosorbents, freeze-dried composite had higher adsorption capacity and better stability. The capacity of adsorption was found to be Cu(II) (0.417 mmol/g) > Zn(II) (0.303 mmol/g) > Cr(VI) (0.251 mmol/g) > Ni(II) (0.225 mmol/g) > Pb(II) (0.127 mmol/g) at the same initial concentration 5 mmol L,1. In contrast to some other chitosan-type biosorbenrts, preparation and component of the biosorbent were obviously more environment friendly. Moreover, adsorption capacity of chitosan in the blending biosorbent could be fully shown. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Delivery of nerve growth factor to brain via intranasal administration and enhancement of brain uptakeJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 10 2009Siva Ram Kiran Vaka Abstract The main objective of the study was to investigate the efficacy of chitosan to facilitate brain bioavailability of intranasally administered nerve growth factor (NGF). In vitro permeability studies and electrical resistance studies were carried out across the bovine olfactory epithelium using Franz diffusion cells. The bioavailability of intranasally administered NGF in rat hippocampus was determined by carrying out brain microdialysis in Sprague,Dawley rats. The in vitro permeation flux across the olfactory epithelium of NGF solution without chitosan (control) was found to be 0.37,±,0.06 ng/cm2/h. In presence of increasing concentration of chitosan (0.1%, 0.25%, and 0.5%, w/v) the permeation flux of NGF was found to be 2.01,±,0.12, 3.88,±,0.19, and 4.12,±,0.21 ng/cm2/h respectively. Trans-olfactory epithelial electrical resistance decreased ,34.50,±,4.06% in presence of 0.25% (w/v) chitosan. The Cmax in rats administered with 0.25% (w/v) chitosan and NGF was 1008.62,±,130.02 pg/mL, which was significantly higher than that for rats administered with NGF only 97.38,±,10.66 pg/mL. There was ,14-fold increase in the bioavailability of intranasally administered NGF with chitosan than without chitosan. Chitosan can enhance the brain bioavailability of intranasally administered NGF. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:3640,3646, 2009 [source] Use of chitosan-alginate as alternative pelletization aid to microcrystalline cellulose in extrusion/spheronizationJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 9 2007Nattawut Charoenthai Abstract Two types of different molecular weight chitosan were investigated as a pelletization aid in extrusion/spheronization using water as granulation liquid. Spherical pellets with a maximum fraction of 60% w/w chitosan could be produced when 1.25,2.5% w/w sodium alginate was included in the formulations with no microcrystalline cellulose (MCC). Chitosan with lower molecular weight of 190 kDa showed a better pellet forming property. The pellets obtained had acceptable physical characteristics and a fast drug release. The results from Fourier transform infrared spectroscopy, differential scanning calorimetry and 13C CP-MAS nuclear magnetic resonance spectroscopy confirmed the formation of polyelectrolyte complex (PEC) between chitosan and sodium alginate, which might be a reason for successful pelletization by extrusion/spheronization. Moreover, the presence of PEC might influence the physical characteristics and dissolution behavior of chitosan-alginate pellets. The results indicated an achievement in production of pellets by extrusion/spheronization without using MCC. Moreover, chitosan combined with sodium alginate could be used as a promising alternative pelletization aid to MCC in extrusion/spheronization. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96: 2469,2484, 2007 [source] Chitosan,alginate,CaCl2 system for membrane coat applicationJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 8 2001Lishan Wang Abstract Water-based formulations are preferred for membrane coat application because they do not require the use of noxious solvents. A novel aqueous chitosan,alginate,CaCl2 system was evaluated as a potential formulation to produce water-insoluble membranes of biodegradable polymers. Chitosan,alginate coacervates were prepared by controlled reaction of chitosan (0.25% w/v) and sodium alginate (0.25% w/v) solutions. Coherent membranes were obtained by casting and drying the coacervates suspended in aqueous CaCl2 solutions (0.05,0.07% w/v). Increasing the calcium content did not modify membrane thickness (25,26 ,m), but reduced the water vapor transmission rate from 658 to 566 g/m2/day, and improved the tensile strength of the membranes from 9.33 to 17.13 MPa. Differential scanning calorimetry, Fourier transform infrared spectroscopy, and elemental analyses of the chitosan,alginate coacervates indicated they were stable for up to 4 weeks of storage in distilled water at ambient temperature. Membranes of the stored coacervates required less calcium to attain maximum mechanical strength. They also had higher water vapor transmission rates than corresponding films prepared from fresh coacervates. On the basis of the properties of the cast film and its storage stability, the chitosan,alginate,CaCl2 system can be considered for potential membrane coat application. © 2001 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 90:1134,1142, 2001 [source] Potential prospects of chitosan derivative trimethyl chitosan chloride (TMC) as a polymeric absorption enhancer: synthesis, characterization and applicationsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 9 2008Jasjeet K. Sahni ABSTRACT In recent years, researchers have been working extensively on various novel properties of polymers to develop increased efficiency of drug delivery and improve bioavailability of various drug molecules, especially macromolecules. Chitosan, a naturally occurring polysaccharide, because of its protonated/polymeric nature, provides effective and safe absorption of peptide and protein drugs. Its transmucosal absorption is, however, limited to acidic media because of its strong intermolecular hydrogen bonds. A new partially quaternized chitosan derivative, N-trimethyl chitosan chloride (TMC), has been synthesized with improved solubility, safety and effectiveness as an absorption enhancer at neutral pH and in aqueous environment. It enhances the absorption, especially of peptide drugs, by reversible opening of tight junctions in between epithelial cells, thereby facilitating the paracellular diffusion of peptide drugs. This derivative thus opens new perspectives as a biomaterial for various pharmaceutical applications/drug delivery systems. This review deals with the potential use of the quaternized chitosan derivative as a permeation enhancer for the mucosal delivery of macromolecular drugs along with its other biomedical applications. [source] Advances and potential applications of chitosan derivatives as mucoadhesive biomaterials in modern drug deliveryJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 8 2006Shruti Chopra Pharmaceutical technologists have been working extensively on various mucoadhesive polymeric systems to create an intimate and prolonged contact at the site of administration. Chitosan is one of the most promising polymers because of its non-toxic, polycationic biocompatible, biodegradable nature, and particularly due to its mucoadhesive and permeation enhancing properties. Due to its potential importance in controlled drug delivery applications, pharmaceutical scientists have exploited this mucoadhesive polymer. However, chitosan suffers from limited solubility at physiological pH and causes presystemic metabolism of drugs in intestinal and gastric fluids in the presence of proteolytic enzymes. These inherent drawbacks of chitosan have been overcome by forming derivatives such as carboxylated, various conjugates, thiolated, and acylated chitosan, thus providing a platform for sustained release formulations at a controlled rate, prolonged residence time, improved patient compliance by reducing dosing frequency, enhanced bioavailability and a significant improvement in therapeutic efficacy. We have explored the potential benefits of these improved chitosan derivatives in modern drug delivery. [source] Antitumour Activity and Side Effects of Combined Treatment with Chitosan and Cisplatin in Sarcoma 180-Bearing MiceJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 7 2000YOSHIYUKI KIMURA We examined the possible modulation by chitosan of the antitumour effects and side effects of cisplatin (cis-diaminedichloroplatinum, CDDP). The study showed that CDDP had potent antitumour activity when administered orally as well as intraperitoneally. We also compared the antitumour activity and side effects of orally administered CDDP plus orally administered chitosan versus intraperitoneally administered CDDP plus orally administered chitosan in sarcoma 180-bearing mice. When CDDP (1.25 mg kg,1 × 2 day,1) was intraperitoneally administered to sarcoma 180-bearing mice, myelotoxicity (the reduction of leucocyte and platelet numbers), nephrotoxicity (the increase of blood nitrogen urea level), immunotoxicity (the reduction of spleen and thymus weight) and a reduction in body weight resulted. These intraperitoneally administered CDDP-induced side effects were not prevented by oral administration of chitosan (150 mg kg,1 × 2 day,1 and 750 mg kg,1 × 2 day,1) for 14 consecutive days. On the other hand, the side effects such as the reductions of body and spleen weights induced by orally administered CDDP (1.25 mg kg,1 × 2 day,1) were prevented by the oral administration of chitosan (150 mg kg,1 × 2 day,1 and 750 mg kg,1 × 2 day,1). From these results, we conclude that the orally administered chitosan plus CDDP might be useful for the prevention of body weight reduction and immunotoxicity (the reduction of spleen weight) induced by the orally administered CDDP without diminishing antitumour activity. [source] | ||||||||||||||||||||||||||||||||||