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Sodium Alginate (sodium + alginate)
Selected AbstractsPreparation and Characterization of Gallium Releasing 3-D Alginate Coated 45S5 Bioglass® Based Scaffolds for Bone Tissue Engineering,ADVANCED ENGINEERING MATERIALS, Issue 7 2010Viviana Mouriño Abstract The aim of this work was to develop functional three-dimensional scaffolds based on Bioglass® derived glass,ceramics for bone tissue engineering (TE) with prophylaxis effect against infections. The highly porous scaffolds were fabricated by the foam replication technique and then coated with sodium alginate crosslinked with Ga3+. It was confirmed that the polymer coating did not affect the interconnectivity of the scaffold pore structure. The resulting composite scaffold exhibited antibacterial effect and improved mechanical properties as well as high bioactivity. The novel Ga3+ loaded 45S5 Bioglass®-based scaffolds coated with alginate are promising candidates for bone TE applications. [source] Physical and Biological Properties of a Novel Hydrogel Composite Based on Oxidized Alginate, Gelatin and Tricalcium Phosphate for Bone Tissue Engineering,ADVANCED ENGINEERING MATERIALS, Issue 12 2007K. Cai A novel hydrogel composite is reported in this study, which was derived from oxidized alginate, gelatin and tricalcium phosphate (TCP). The physical and biological properties of these hydrogel composites prepared with oxidized sodium alginate with different oxidation degrees were investigated. The drug delivery potential of this hydrogel composite as a carrier was evaluated by using Vitamin B2 as a model drug as well. An in vitro investigation with encapsulation of osteoblast revealed that these composites were biocompatible. This hydrogel composite presented here may be utilized for the fabrication of potential injectable systems for tissue engineering, drug delivery and other medical applications. [source] Spinning of protein fibres from blue squat lobster (Cervimunida jhoni) industry by-productsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 6 2007Mario Pérez-Won Summary The fresh whole crustaceans by-products from blue squat lobster (Cervimunida jhoni) were minced and the protein was solubilised with 0.1 m of NaOH. Then the solution was centrifuged and the supernatant was precipitated using 0.1 m of HCl. The dope was prepared with 4% of protein, solid NaOH and coadjutant (sodium alginate or carragenan). The dope was extruded through the trial-spinning machine and the fibre was formed. The results showed that the best condition of protein extraction was 90 min and pH 12.5 when 58.4% of protein from whole crustacean by-products could be extracted. The protein isolate was obtained at pH 4.0. The best fibres were obtained when the ratios protein/NaOH, and protein/coadjutant were 10:1 and 1:1 respectively. Rheological measurements of all dopes exhibited non-Newtonian behaviour and the experimental data were described by the power law model. The consistency index (k) of the dopes containing carragenan seem to be a parameter to evaluate dope spinnability. [source] Irradiation synthesis of biopolymer-based superabsorbent hydrogel: Optimization using the Taguchi method and investigation of its swelling behaviorADVANCES IN POLYMER TECHNOLOGY, Issue 2 2009Ghasem R. Bardajee Abstract In this report, the synthesis of a novel superabsorbent hydrogel via ,-irradiation graft copolymerization of acrylamide onto sodium alginate and kappa-carrageenan hybrid backbones in a homogeneous solution is described. The Taguchi method was used as a powerful experimental design tool for synthesis optimization. A series of superabsorbent hydrogels was synthesized by proposed conditions of Qualitek-4 software. Considering the results of nine trials according to analysis of variance, optimum conditions were proposed. The swelling behavior of optimum superabsorbent hydrogels was studied in various solutions, with pH values ranging from 1 to 13. In addition, swelling kinetics, swelling in various organic solvents, the absorbency under load, and on,off switching behavior were investigated. Also, hydrogel formation was confirmed by Fourier transform infrared spectroscopy. Surface morphology of the synthesized hydrogels was assessed by scanning electron microscopy. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 28:131,140, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20154 [source] Preparation and in vitro evaluation of new pH-sensitive hydrogel beads for oral delivery of protein drugsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010I. M. El-Sherbiny Abstract New biodegradable pH-responsive hydrogel beads based on chemically modified chitosan and sodium alginate were prepared and characterized for the controlled release study of protein drugs in the small intestine. The ionotropic gelation reaction was carried out under mild aqueous conditions, which should be appropriate for the retention of the biological activity of an uploaded protein drug. The equilibrium swelling studies were carried out for the hydrogel beads at 37°C in simulated gastric (SGF) and simulated intestinal (SIF) fluids. Bovine serum albumin (BSA), a model for protein drugs was entrapped in the hydrogels and the in vitro drug release profiles were established at 37°C in SGF and SIF. The preliminary investigation of the hydrogel beads prepared in this study showed high entrapment efficiency (up to 97%) and promising release profiles of BSA. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Pervaporation separation of sodium alginate/chitosan polyelectrolyte complex composite membranes for the separation of water/alcohol mixtures: Characterization of the permeation behavior with molecular modeling techniquesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2007Sang-Gyun Kim Abstract Polyelectrolyte complex (PEC) membranes were prepared by the complexation of protonated chitosan with sodium alginate doped on a porous, polysulfone-supporting membrane. The pervaporation characteristics of the membranes were investigated with various alcohol/water mixtures. The physicochemical properties of the permeant molecules and polyion complex membranes were determined with molecular modeling methods, and the data from these methods were used to explain the permeation of water and alcohol molecules through the PEC membranes. The experimental results showed that the prepared PEC membranes had an excellent pervaporation performance in most aqueous alcohol solutions and that the selectivity and permeability of the membranes depended on the molecular size, polarity, and hydrophilicity of the permeant alcohols. However, the aqueous methanol solutions showed a permeation behavior different from that of the other alcohol solutions. Methanol permeated the prepared PEC membranes more easily than water even though water molecules have stronger polarity and are smaller than methanol molecules. The experimental results are discussed from the point of view of the physical properties of the permeant molecules and the membranes in the permeation state. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2634,2641, 2007 [source] Influence of anti-washout agents on the rheological properties and injectability of a calcium phosphate cementJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2007Xiupeng Wang Abstract Anti-washout-type calcium phosphate cement (aw-CPC) was prepared by introducing chitosan, sodium alginate, or modified starch into the powder phase of CPC, respectively. The results showed that these cements cannot be washed out and set within approximately 10,30 min even if the pastes were immersed in distilled water immediately and were shaken in a shaker after mixing and moulding. To our knowledge, it is the first report about the influence of the content of these anti-washout additives on the rheological properties and injectability of the cement. Moreover, novel approach of yield stress measurement was used to evaluate the injectability of the pastes. A modified starch was originally used as anti-washout agent for CPC. This study provided a convenient way to use the injectable CPC with good anti-washout performance when the paste was exposed to blood. The aw-CPC had potential prospects for the wider applications in surgery such as orthopaedics, oral, and maxillofacial surgery. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [source] Chitosan-alginate films prepared with chitosans of different molecular weightsJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 4 2001Xiao-Liang Yan Abstract Chitosan-alginate polyelectrolyte complex (CS-AL PEC) is water insoluble and more effective in limiting the release of encapsulated materials compared to chitosan or alginate. Coherent CS-AL PEC films have been prepared in our laboratory by casting and drying suspensions of chitosan-alginate coacervates. The objective of this study was to evaluate the properties of the CS-AL PEC films prepared with chitosans of different molecular weights. Films prepared with low-molecular-weight chitosan (Mv 1.30 × 105) were twice as thin and transparent, as well as 55% less permeable to water vapor, compared to films prepared with high-molecular-weight chitosan (Mv 10.0 × 105). It may be inferred that the low-molecular-weight chitosan reacted more completely with the sodium alginate (Mv 1.04 × 105) than chitosan of higher molecular weight. A threshold molecular weight may be required, because chitosans of Mv 10.0 × 105 and 5.33 × 105 yielded films with similar physical properties. The PEC films exhibited different surface properties from the parent films, and contained a higher degree of chain alignment with the possible formation of new crystal types. The PEC films exhibited good in vitro biocompatibility with mouse and human fibroblasts, suggesting that they can be further explored for biomedical applications. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 58: 358,365, 2001 [source] Effectiveness test of alginate-derived polymeric surfactantsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2002Hyun-Ah Kang Abstract A series of alginate-derived polymeric surfactants (APSs) with a linear alkyl group (C8, C12, C16) was synthesized by oxidation followed by reductive amination of 2,3-dialdehydic alginate. The products were characterized by measuring IR spectra, NMR spectra, surface tension and critical micelle concentration (cmc). They were also tested for the solubilization of azobenzene and adsorption of heavy metal. In the case of 40% CHO-C8 APSs, the lowest interfacial tension value (31.5,m Nm,1) was obtained at the cmc value of 1.35,g,dm,3. The dissolving capacity of 40% CHO-C8 APS towards azobenzene was 27 times greater than that of alginate. The overall cobalt (Co2+) removal efficiency by adsorption using APSs was high compared with that of sodium alginate at pH 3, 5 and 7. Equilibrium aspects of cobalt adsorption onto 10% CHO-APSs were studied, and the results show that APSs had high equilibrium capacities for cobalt uptake, 115.5,mgg,1. © 2002 Society of Chemical Industry [source] OPTIMIZATION OF NEW FLOUR IMPROVER MIXING FORMULA BY SURFACE RESPONSE METHODOLOGYJOURNAL OF FOOD PROCESS ENGINEERING, Issue 2 2010RAOUDHA ELLOUZE GHORBEL ABSTRACT In the present study, we search to improve the viscoelastic properties of wheat flour characterized by a low bread-making quality. Six regulators were tested: broad bean flour, gluten, monodiglyceride (MDG), ascorbic acid, sodium alginate and a mixture of amylase and xylanase. A hybrid design was carried out in order to study the effect of these regulators on the alveographic properties of wheat flour dough. Two alveographic responses (W: deformation energy and P/L: elasticity-to-extensibility ratio) were studied and simultaneously optimized via the desirability functions. An optimal mixture, containing 13.17 g/kg of broad bean flour, 15.13 g/kg of gluten, 0.155 g/kg of ascorbic acid, 3.875 g/kg of MDG, 2.75 g/kg of sodium alginate and 0.3 g/kg of enzyme mixture, was obtained and tested in a Tunisian flour. It led to a dough characterized by a W = 274 × 10,4 J and P/L = 0.74 versus 191 × 10,4 J and 0.40, respectively, for the Tunisian flour without improvers. PRACTICAL APPLICATIONS In this work, we developed a new flour improver mixing formula intended to be used with wheat flour characterized by a low bread-making quality. This improver mixture is in powder form and contains 13.17 g of broad bean flour, 15.13 g of gluten, 0.155 g of ascorbic acid, 3.875 g of monodiglyceride, 2.75 g of sodium alginate and 0.3 g of enzyme mixture per kilogram of wheat flour. The incorporation of this improver mixture in low bread-making quality wheatflour leads to an increase of its deformation energy (W) of about 43% and produces large volume bread. [source] Interactions of ,-carrageenan Plus Other Hydrocolloids in Fish Myosystem GelsJOURNAL OF FOOD SCIENCE, Issue 6 2001M. Pérez-Mateos ABSTRACT: Mixtures of ,-carrageenan plus other hydrocolloids (locust bean, guar, xanthan, iota-carrageenan, sodium carboxymethylcellulose, and sodium alginate) were examined for their effects on the mechanical and water holding properties of heat-induced gels made from washed blue whiting mince. Gel structure and thermal behavior were also studied. No synergistic effect was detectable through functional properties except for the mixture of ,-carrageenan with locust bean gum. Light microscopy revealed that ,-carrageenan and xanthan mixed locally with locust bean at its rich domains. ,-carrageenan and xanthan presented interactions with the protein matrix, which were more discernible in the first case. Differential scanning calorimetry (DSC) revealed faint interactions for the mixtures of ,-carrageenan with locust bean and with xanthan, and weakly synergistic gelling effects between the last two hydrocolloids. The blend of ,-carrageenan with sodium alginate exhibited thermally strong synergistic interactions but no particular effects were induced on corresponding functional properties. [source] Interfacial and foaming characteristics of milk whey protein and polysaccharide mixed systemsAICHE JOURNAL, Issue 4 2010Adrián A. Perez Abstract Protein-polysaccharide (PS) interactions find many applications in food engineering and new foam formulations. In this article, we have studied the effect of anionic nonsurface active PSs [sodium alginate (SA) and lambda-carrageenan (,-C)] in aqueous solution on interfacial and foaming characteristics of milk whey proteins [whey protein concentrate (WPC) and whey protein isolate (WPI)]. Whey protein concentration (1.0% wt), temperature (20°C), pH (7), and ionic strength (0.05 M) of the aqueous media were kept constant, while PS influence was evaluated within a 0.0,1.0% wt concentration range. The dynamic properties (dynamics of adsorption and surface dilatational properties) of WPC/PS and WPI/PS adsorbed films were considered in order to correlate the foaming characteristics of the biopolymer mixed systems. Foaming characteristics of the biopolymer mixed systems depended on the PS relative concentration in the aqueous phase and on the whey protein-PS interactions in solution and at the air,water interface. Dynamic surface properties of the adsorbed films at short adsorption time had a significant effect on foaming capacity. For a particular system, the overall foam destabilization (foam half-life time) and the individual destabilization processes (drainage, disproportionation, and bubble coalescence) depend on the nature of the PS, its relative bulk concentration, and whey protein-PS interactions in the vicinity of the air,water interface. The viscosity of the aqueous phase has an effect on the rate of drainage while the rate of disproportionation/collapse is more dependent on the interfacial characteristics of the adsorbed film. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [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] Textural profiling and statistical optimization of crosslinked calcium-alginate-pectinate-cellulose acetophthalate gelisphere matricesJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 12 2002Viness Pillay Abstract A 25 factorial design was employed to statistically evaluate the textural properties of a crosslinked calcium-alginate-pectinate-cellulose acetophthalate gelisphere system. In accordance with the factorial matrix, gelispheres were formulated by titrating a combination polymeric solution comprised of sodium alginate, pectin and/or cellulose acetophthalate into an inducer solution (crosslinking agent) consisting of calcium and/or acetate ions. A Texture Analyzer was used to profile the gelisphere matrices for their resilience in the unhydrated and hydrated states, the fracture energy involved in matrix rupture, and the matrix hardness achieved with different levels of crosslinking. Significantly different textural properties were found among the crosslinked formulations. In particular, the unhydrated matrix resilience was selected as a parameter for optimization of the gelisphere formulation because of its large impact on drug release modulation, matrix integrity, and sensitivity to the crosslinking process. Resilience increased with increasing polymer concentration, irrespective of the polymer combination. Furthermore, resilience was not significantly influenced by the concentration of the crosslinking agents, but rather by the application of a higher polymer concentration in the crosslinking reaction; again irrespective of the polymer combination. In addition to the use of a factorial design, artificial neural modeling was employed to predict the textural properties based on the factorial matrix as a statistically suitable data source. Neural networks appeared to be a strong competitor of factorial regression for the prediction of textural data. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:2559,2570, 2002 [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] Polymer film formulations for the preparation of enteric pharmaceutical capsulesJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 2 2010Alan M. Smith Abstract Objectives Standard pharmaceutical capsules are designed to dissolve in the acidic environment of the stomach releasing the encapsulated contents for absorption. When release is required further along the gastrointestinal tract capsules can be coated with acid insoluble polymers to enable passage through the stomach and dissolution in the intestine. This paper describes formulations that have the potential to be used to produce two-piece hard capsules for post-gastric delivery without the requirement of an exterior coat. Methods The formulation uses three polysaccharides: sodium alginate, hypromellose and gellan gum to provide acid insolubility and the ability to form capsules using standard industrial equipment. Key findings The rheological profile, on cooling, of the base material, water content and thickness of the films were shown to be comparable with those of commercial capsules. The capsules remained intact for 2 h in 100 mm HCl at pH 1.2, and within 5 min of being removed from the acid and submerged in phosphate-buffered saline at pH 6.8 were ruptured. Conclusions Selected formulations from this study have potential for use as delayed release capsules. [source] Controlled release tamsulosin hydrochloride from alginate beads with waxy materialsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 12 2005Min-Soo Kim The objective of this study was to develop oral controlled release delivery systems for tamsulosin hydrochloride (TSH) using alginate beads with various waxy materials, such as Compritol 888 ATO, Precirol ATO 5 and Gelucires. The beads were prepared from sodium alginate,waxy material,TSH slurry dropped onto calcium chloride to form spherical beads. The effects of the addition of various waxy materials to alginate beads on the drug encapsulation efficiency, bead size and morphology were investigated. The drug encapsulation efficiency significantly increased with the addition of waxy materials. The TSH-loaded alginate beads with and without waxy materials were almost spherical particles with an average diameter of 1.44 and 1.22mm, respectively. In dissolution study, the TSH-loaded alginate beads with waxy materials exhibited controlled release behaviour over a 6-h period, while beads without waxy materials showed release of 100% TSH within 2h. These results may be attributed to the formation of a more rigid alginate matrix structure due to incorporated waxy materials. From the Dunnett's t -test and the f2 factor, the release of TSH from alginate beads, a similar dissolution pattern to that of the marketed product (Harunal capsules) could be achieved by adding Gelucire 50/13 into TSH-loaded alginate beads. From these results, oral controlled release of TSH could be achieved with loading in alginate beads with waxy materials, such as Compritol 888 ATO, Precirol ATO 5 and Gelucires. [source] Influence of magnesium aluminium silicate on rheological, release and permeation characteristics of diclofenac sodium aqueous gels in-vitroJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 4 2005Thaned Pongjanyakul The effect of magnesium aluminium silicate (MAS) on rheological, release and permeation characteristics of diclofenac sodium (DS) aqueous gels was investigated. DS aqueous gels were prepared using various gelling agents, such as 15% w/w poloxamer 407 (PM407), 1% w/w hydroxypropylmethylcellulose (HPMC), and 1% w/w high and low viscosity grades of sodium alginate (HV-SA and LV-SA, respectively). Different amounts of MAS (0.5, 1.0 and 1.5% w/w) were incorporated into the DS gels. Incorporation of MAS into the DS gels prepared using SA or PM407 caused a statistical increase in viscosity (P<0.05) and a shift from Newtonian flow to pseudoplastic flow with thixotropic property. The DS release rates of these composite gels were significantly decreased (P<0.05) when compared with the control gels. This was due to an interaction between MAS and PM407 or SA, and adsorption of DS onto MAS particles. Moreover, a longer lag time and no change in DS permeation flux were found when MAS was added to the gels. The findings suggest that the rheological characteristics of gels prepared using PM407 or SA could be improved by incorporating MAS. However, the use of MAS could retard the DS release and extend the lag time of DS permeation. [source] Mucoadhesive microspheres for nasal administration of an antiemetic drug, metoclopramide: in-vitro/ex-vivo studiesJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 3 2005Elisabetta Gavini Microparticulate delivery systems designed for the nasal administration of an antiemetic drug, metoclopramide hydrochloride, were prepared. Microspheres composed of sodium alginate, chitosan hydrochloride, or both, were obtained using a spray-drying method; some batches of drug-free microparticles were prepared as a comparison. The morphology, in-vitro swelling behaviour, mucoadhesive properties and drug release from microparticles were evaluated. Ex-vivo drug permeation tests were carried out using sheep nasal mucosa; permeation test of the drug solution was peformed as comparison. During ex-vivo permeation tests, transmission electron microscopy (TEM) analyses were carried out on the nasal mucosa to study the morphological changes of epithelial cells and tight junctions, while the change in microsphere morphology was examined using photostereo microscopy (PM). Spray-dried microparticles had a mean diameter (dvs) in the range of about 3,10 ,m. They showed good in-vitro mucoadhesive properties. In-vitro release profiles and swelling behaviour depended on their composition: the drug release occurred in 1,3 h. Ex-vivo studies showed that drug permeation through the mucosa from microparticles based on chitosan was higher than from those consisting of alginate alone. This can be related to the penetration enhancing properties of chitosan. Complexation of chitosan with alginate led to a control of the drug release. Microscopy observation of microspheres during the permeation tests revealed that microparticles swelled and gelled, maintaining their shape. TEM analyses of the mucosa after exposure to the microparticles consisting of alginate/chitosan showed opened tight junctions. This preliminary study shows that alginate/chitosan spray-dried microspheres have promising properties for use as mucoadhesive nasal carriers of an antiemetic drug. [source] Cryoprotective additives and cryostabilisation effects on muscle fillets of the freshwater teleost fish Rohu carp (Labeo rohita) during prolonged frozen storageJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 15 2006Shashi Kiran Jasra Abstract The effects of various cryoprotective additives separately and in combination were studied on the myofibrillar protein integrity, biochemical enzyme activity levels and muscle ultrastructure in the freshwater teleost fish Rohu carp (Labeo rohita). Fish muscle samples were divided into eight groups and immersed in different mixtures of cryoprotective additives (S1,S8), then frozen at , 20 or , 30 °C for 24 months. Electrophoretic studies revealed early (within 6 months) alteration of the myofibrillar proteins myosin light chain, ,-actinin and tropomyosin. Reduction of the storage temperature from , 20 to , 30 °C slowed down the degradative processes. Sodium dodecyl sulfate polyacrylamide gel electrophoresis indicated that fish muscle treated with cryoprotective mixture S8 (40 g L,1 sorbitol/3 g L,1 sodium tripolyphosphate/4 g L,1 sodium alginate) showed minimal post mortem changes in myofibrillar proteins. Ultrastructural results also revealed post mortem damage to the muscle, seen earliest (within 6 months) in the sample frozen-stored without additives (S2), as compared with the normal, unfrozen muscle (S1). The influence of cryoprotectants alone and in combination on fish muscle structural proteins, myosin and actin filaments (A and I bands), during prolonged frozen storage was investigated. After 12 months, samples frozen-stored with various cryoprotective additives (S2-S7), except S8, showed signs of myofibrillar disintegration. Beyond that time the degradative processes started showing up in all samples, with minimal muscle ultrastructural damage in sample S8. Again, reducing the storage temperature from , 20 to , 30 °C slowed down the degradative processes. Ultrastructural results correlated well with levels of biochemical enzymes (Ca2+ myofibrillar ATPase and succinic dehydrogenase) during frozen storage. This is the first report of the cryoprotective effects of these additives on this popular edible fish species. Of the various combinations of additives tested, cryoprotective mixture S8 was found to preserve the muscle structure longest under frozen storage conditions. However, even this mixture was only effective for 18 months at , 30 °C. Beyond that time the myofibrillar degradative processes were apparent with correlative electrophoretic, biochemical and ultrastructural studies. Copyright © 2006 Society of Chemical Industry [source] Degradation of malic acid in wine by immobilized Issatchenkia orientalis cells with oriental oak charcoal and alginateLETTERS IN APPLIED MICROBIOLOGY, Issue 5 2010S.K. Hong Abstract Aims:, To test degradation of malic acid content in wine by immobilized Issatchenkia orientalis KMBL 5774 cells recently isolated from Korean wine pomace as a malic acid-degrading yeast. Methods and Results:,I. orientalis KMBL 5774 cells were immobilized using a mixture of oriental oak (Quercus variabilis) charcoal with sodium alginate. When the immobilized yeast cells were observed on a scanning electron microscope, cells were efficiently immobilized on the surface area of the charcoal. A Korean wine containing a high level of malic acid was treated with the immobilized yeast cells. The HPLC analysis of the malic acid content in the treated wine showed the malic acid content was reduced to 0·75 mg ml,1 after treatment from the original content of 8·96 mg ml,1, representing 91·6% of the malic acid was degraded during the treatment. Conclusions:, The immobilization of the malic acid-degrading yeasts with oriental oak charcoal and sodium alginate is useful for degradation of malic acid in wines containing a high level of malic acid with no significant increase in other acids. Significance and Impact of the study:, Malic acid is sometimes detrimental to the quality of wines when present at high concentrations in some varieties. The immobilized I. orientalis KMBL5774 cells appear to be a promising candidate in view of developing biotechnological methods for reduction of malic acid contents in wine. [source] Resistance to oxidative stress caused by ceftazidime and piperacillin in a bio,lm of PseudomonasLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 5 2004Paola C. Battán Abstract The capacity to form a bio,lm was evaluated in Pseudomonas aeruginosa isolated from patients with lung and urinary infections. Adherence, development of microcolonies and slime formation varied in the studied strains. P. aeruginosa P63 isolated from cystic ,brosis (CF) exhibited important microcolony formation with the densest bio,lm, and was selected to study the oxidative stress produced with ceftazidime and piperacillin by means of chemiluminescence (CL) in cell suspensions and bio,lm. P. aeruginosa strain P63 was compared with P69; both were sensitive to ceftazidime and showed increase of reactive species of oxygen (ROS) in the presence of this antibiotic. P. aeruginosas P69 exhibited resistance to piperacillin and low ROS production, while piperacillin-sensitive strain P63 showed high oxidative stress with this antibiotic. Piperacillin stimulated oxidative stress, increasing ROS production only in the sensitive strain. Higher antibiotic concentrations were necessary to augment ROS in bacteria bio,lm than in suspension. Incubation of P63 strain with ceftazidime or piperacillin in the presence of its own extracellular matrix (EM) or sodium alginate stimulated lesser oxidative stress and slower decrease of ROS than in the absence of these polysaccharides. A variant, V10, obtained from strain P63 showed more sensitivity to the antibiotics than the wild-type, and concomitantly exhibited higher production of ROS in the presence of both the antibiotics studied. Copyright © 2004 John Wiley & Sons, Ltd. [source] Microgel-Based Engineered Nanostructures and Their Applicability with Template-Directed Layer-by-Layer Polyelectrolyte Assembly in Protein EncapsulationMACROMOLECULAR BIOSCIENCE, Issue 5 2005Dinesh B. Shenoy Abstract Summary: A novel strategy for the fabrication of microcapsules is elaborated by employing biomacromolecules and a dissolvable template. Calcium carbonate (CaCO3) microparticles were used as sacrificial templates for the two-step deposition of polyelectrolyte coatings by surface controlled precipitation (SCP) followed by the layer-by-layer (LbL) adsorption technique to form capsule shells. When sodium alginate was used for inner shell assembly, template decomposition with an acid resulted in simultaneous formation of microgel-like structures due to calcium ion-induced gelation. An extraction of the calcium after further LbL treatment resulted in microcapsules filled with the biopolymer. The hollow as well as the polymer-filled polyelectrolyte capsules were characterized using confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), and scanning force microscopy (SFM). The results demonstrated multiple functionalities of the CaCO3 core , as supporting template, porous core for increased polymer accommodation/immobilization, and as a source of shell-hardening material. The LbL treatment of the core-inner shell assembly resulted in further surface stabilization of the capsule wall and supplementation of a nanostructured diffusion barrier for encapsulated material. The polymer forming the inner shell governs the chemistry of the capsule interior and could be engineered to obtain a matrix for protein/drug encapsulation or immobilization. The outer shell could be used to precisely tune the properties of the capsule wall and exterior. Confocal laser scanning microscopy (CLSM) image of microcapsules (insert is after treating with rhodamine 6G to stain the capsule wall). [source] Release of potassium sorbate from active films of sodium alginate crosslinked with calcium chloridePACKAGING TECHNOLOGY AND SCIENCE, Issue 6 2009E. M. Zactiti Abstract The release of potassium sorbate from alginate films was evaluated considering different active agent concentrations in the film and three levels of alginate crosslinking. The mechanism involved in the diffusional process was investigated using the Power Law Model. The results indicated that potassium sorbate diffusion in alginate films has characteristics of Fickian and non-Fickian behaviour. Effective diffusion coefficients obtained using the solution in series derived from Fick's Second Law are close to values obtained by the short-time solution, indicating that the influence of swelling on effective diffusivity, although perceptible, is small, allowing the use of an average effective diffusivity. The values of effective diffusivity found indicate that alginate films have a potential use as systems for release of active substances. Copyright © 2009 John Wiley & Sons, Ltd. [source] Synthesis, characterization, mechanical properties and biocompatibility of interpenetrating polymer network,super-porous hydrogel containing sodium alginatePOLYMER INTERNATIONAL, Issue 12 2007Lichen Yin Abstract In this investigation an interpenetrating polymer network,superporous hydrogel containing sodium alginate (IPN-SPHAlg) was synthesized. The morphology of the polymer was characterized using scanning electron microscopy, light images and porosity, and the polymer was further examined by swelling ratio, mechanical strength and biocompatibility. The results indicated that the IPN-SPHAlg possessed both large numbers of interconnected pores and an interpenetrating network. The swelling ratio of IPN-SPHAlg was lower than that of the superporous hydrogel (SPH) and it decreased as the sodium alginate/monomer ratio increased. The IPN-SPHAlg exhibited pH responsiveness and salt-sensitive properties. Compared to SPH and SPH composites, the mechanical strength of IPN-SPHAlg was significantly enhanced. Thiazolyl blue assay on AD293 cells, in situ lactate dehydrogenase assay and morphological study of rat intestine showed that the polymer induced no significant cell or mucosal damage. The fast swelling, good mechanical properties, pH sensitivity and biocompatibility of the IPN-SPHAlg suggested it as a potential candidate in the field of drug-delivery systems. Copyright © 2007 Society of Chemical Industry [source] The controlled release behavior and pH- and thermo-sensitivity of alginate/poly(vinyl alcohol) blended hydrogelsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 8 2009Win-Chun Jao Abstract Poly(vinyl alcohol) (PVA) was blended with sodium alginate (Alg) in various ratios and crosslinked with calcium chloride and made into hydrogel membranes. The dependence of the swelling behavior of these Alg-Ca/PVA hydrogels on pH was investigated. The temperature-dependent swelling behavior of the semi-interpenetrating network (semi-IPN) hydrogels was examined at temperatures from 2 to 45°C and the enthalpy of mixing (,Hmix) was determined at various temperatures. The molecular structure of the hydrogels was studied by infrared spectroscopy and their water structure in the semi-IPN hydrogels was measured by differential scanning calorimetry (DSC). The influence of Ca2+ content on the network structure of Alg-Ca/PVA hydrogels was investigated in terms of the compressive elastic modulus, effective crosslinking density, and the polymer,solvent interaction parameter based on the Flory theory. The loading of alizarin red S (ARS) followed the Langmuir isotherm mechanism and the release kinetics of ARS from the Alg-Ca/PVA hydrogels followed the Fickian diffusion mechanism. Copyright © 2008 John Wiley & Sons, Ltd. [source] Entrapment of dispersed pancreatic islet cells in CultiSpher-S macroporous gelatin microcarriers: Preparation, in vitro characterization, and microencapsulationBIOTECHNOLOGY & BIOENGINEERING, Issue 6 2001S. Del Guerra Abstract Immunoprotection of pancreatic islets for successful allo- or xenotransplantation without chronic immunosuppression is an attractive, but still elusive, approach for curing type 1 diabetes. It was recently shown that, even in the absence of fibrotic overgrowth, other factors, mainly insufficient nutrition to the core of the islets, represent a major barrier for long-term survival of intraperitoneal microencapsulated islet grafts. The use of dispersed cells might contribute to solve this problem due to the conceivably easier nutritional support to the cells. In the present study, purified bovine islets, prepared by collagenase digestion and density gradient purification, and dispersed bovine islet cells, obtained by trypsin and DNAsi (viability > 90%), were entrapped into either 2% (w/v) sodium alginate (commonly used for encapsulation purposes) or (dispersed islet cells only) macroporous gelatin microcarriers (CulthiSpher-S, commonly used for the production of biologicals by animal cells). Insulin release studies in response to glucose were performed within 1 week and after 1 month from preparation of the varying systems and showed no capability of dispersed bovine islet cells within sodium alginate microcapsules to sense glucose concentration changes. On the contrary, bovine islet cells entrapped in CulthiSpher-S microcarriers showed maintained capacity of increasing insulin secretion upon enhanced glucose concentration challenge. In this case, insulin release was approximately 60% of that from intact bovine islets within sodium alginate microcapsules. MTT and hematoxylineosin staining of islet cell-containing microcarriers showed the presence of viable and metabolically active cells throughout the study period. This encouraging functional data prompted us to test whether the microcarriers could be immunoisolated for potential use in transplantation. The microcarriers were embedded within 3% sodium alginate, which was then covered with a poly-L-lysine layer and a final outer alginate layer. Maintained insulin secretion function of this system was observed, which raises the possibility of using microencapsulated CulthiSpher-S microcarriers, containing dispersed pancreatic islet cells, in experimental transplantation studies. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 741,744, 2001. [source] | ||||||||||||||||||||||||||||