The effect of alginates on in vitro gastric digestion of particulated whey protein

The aim of the study was to investigate how microparticulated and nanoparticulated whey proteins mixed with alginate respond to simulated in vitro gastric digestion conditions at pH 3.0. Initially, particle size distributions and zeta potential were measured in all mixtures at pH 3.0. Particle size distributions as well as SDS‐PAGE were used to investigate the rate of protein degradation by pepsin during simulated in vitro gastric digestion. The complexation of nanoparticulated and microparticulated whey protein with alginates causes formation of insoluble and soluble complexes, which can resist pepsin degradation to a different degree. These results highlight the potential of developing new food products, which can enhance satiety.     

Influence of the preparation procedure and chitosan type on physicochemical properties and release behavior of alginate–chitosan microparticles

Background: The potential for use of chitosan-treated alginate microparticles as a vehicle for oral phenytoin delivery has not been thoroughly exploited. Aim: We studied the influence of preparation procedure and chitosan type on physicochemical properties and release behavior of alginate-chitosan microparticles. Method: The total number of 24 microparticles formulations prepared by varying contents of calcium gelling ions and varying contents and type of chitosan was examined. As an additional variable, two different hardening times (1 and 24 hours) were employed. Possible interactions of components, surface morphology of microparticles as well as release profile of phenytoin were studied. Results: Both series of formulations with regard to hardening times, irrespective of the chitosan type and/or concentration employed appeared to be highly loaded with the model drug (above 90%). The drug release studies showed that the kinetics of phenytoin cannot be straightforwardly predicted based on the molecular weight of chitosan alone. On the other hand, prolonging the hardening time from 1 to 24 hours had significantly improved phenytoin kinetics, and gave rise to a formulation with the liberation half-time of about 2.5 hours. Conclusion: This study showed that the latter formulation is eligible for further modifications aimed at improving the regularity of phenytoin absorption.     

Influence of process variables and formulation composition on sphericity and diameter of Ca-alginate-chitosan liquid core capsule prepared by extrusion dripping method

ABSTRACT

The influence of process variables and formulation composition on the sphericity and diameter of the alginate capsules which contained dual cations (Ca-and-chitosan) are characterized in this study. Capsule sphericty was not influenced by needle diameter but instead, capsule diameter increased proportionally with the needle diameter. The combined effects of the liquid core solution and alginate solution on the sphericity of the capsules are tabulated. Spherical capsules can be produced when the following criteria were fulfilled: stirring speed is in the range of 240–300 rpm; calcium chloride concentration is >5 g/L; viscosity of liquid core solution is >203 mPa.s; as well as viscosity of alginate solution is in between 47 and 386 mPa.s. The capsule diameter was predicted using a modified Tate’s law equation and an error analysis was conducted to evaluate the equation. The predicted diameter was well correlated with the experimental data with an average absolute deviation <3.6%.     

Sustained-release alginate-chitosan pellets prepared by melt pelletization technique

Context: Alginate-chitosan pellets prepared by extrusion-spheronization technique exhibited fast drug dissolution.

Objective: This study aimed to design sustained-release alginate pellets through rapid in situ matrix coacervation by chitosan during dissolution.

Methods: Pellets made of alginate with chitosan and/or calcium acetate were prepared using solvent-free melt pelletization technique which prevented reaction between processing materials during agglomeration and allowed such reaction to occur only in dissolution phase.

Results: Drug release was retarded in pH 2.2 medium when pellets were formulated with calcium acetate or chitosan till a change in medium pH to 6.8. The sustained-release characteristics of calcium alginate pellets were attributed to pellet dispersion and rapid cross-linking by soluble Ca²⁺ during dissolution. The slow drug release characteristics of alginate-chitosan pellets were attributed to polyelectrolyte complexation and pellet aggregation into swollen structures with reduced erosion. The drug release was, however, not retarded when both calcium acetate and chitosan coexisted in the same matrix as a result of chitosan shielding of Ca²⁺ to initiate alginate cross-linkages and rapid in situ solvation of calcium acetate induced fast pellet dispersion and chitosan losses from matrix.

Conclusion: Similar to calcium alginate pellets, alginate-chitosan pellets demonstrated sustained drug release property though via different mechanisms. Combination of alginate, chitosan and calcium acetate in the same matrix nevertheless failed to retard drug release via complementary drug release pattern.     

Preparation and Physical Characterization of Alginate Microparticles Using Air Atomization Method

Alginate microparticles were prepared using an air atomization method and varying formulation and processing conditions. Thereafter, the size and surface morphology of alginate microparticles were characterized. The trapping efficiencies of the ketoconazole, acetaminophen, vitamin C, and Bifidobacteria bifidum as model core materials were then determined. The air atomization process produced free-flowing and small-size microparticles after the freeze-drying process. The size distribution and surface morphology varied depending on the concentration of wall-forming materials and processing conditions. Generally, the geometric mean size increased as the concentration of alginate and poly-l-lysine and the delivery rate increased, but the air pressure decreased. Most of all, the ratio of delivery rate of alginate solution and air pressure could affect the size and surface morphology of alginate microparticles. However, the geometric mean size of alginate poly-l-lysine microparticles reproducibly ranged from about 80 to 130 μm. The microparticles were irregularly spherical or elliptical. The trapping efficiencies of ketoconazole, acetaminophen, vitamin C, and bifidobacteria were determined to be 71.5%, 60.1%, 1.6%, and 31%, respectively, when alginate concentration (1.5%), poly-l-lysine concentration (0.02%), air pressure (0.75 bar), delivery rate (8 ml/min), and spraying distance (45 cm) were applied. The current microencapsulation process using the air atomization method provides an alternative to entrapping small molecules and macromolecules without using harmful organic solvents. In addition, the small-size and free-flowing alginate microparticles containing active substances can be used as an intermediate in pharmaceutical applications.     

Physical,mechanical and antibacterial properties of alginate film: Effect of the crosslinking degree and oregano essential oil concentration

Alginate films with different degrees of crosslinking obtained by internal gelation, and alginate films incorporated with oregano essential oil (OEO) were prepared. The impact of the degree of crosslinking caused by the use of calcium carbonate as crosslinking agent and the incorporation of OEO into the alginate films on their antibacterial, optical, mechanical, microstructural and water vapour barrier properties was evaluated.     

Techno-economic analysis of processes for Aspergillus carbonarius polygalacturonase production

A techno-economic analysis of submerged (SmF) and solid state fermentation (SSF) processes for Aspergillus carbonarius polygalacturonase production was performed to make an appropriate process selection. The downstream processing involved integrated membrane process (IMP) and alginate affinity precipitation (AAP). For a production scale of 30kL purified polygalacturonase concentrate per year, the total upstream cost of SmF was 14% lower than the SSF process. Downstream processing cost by IMP was 47% lower than AAP. The SmF-IMP process required a total capital investment that was 15-24% lower than the SmF-AAP and SSF-AAP processes. The corresponding unitary product cost was also lower by 24-36% in SmF-IMP process. Thus the SmF-IMP process proved to be very attractive from an economic point of view.     

海藻酸钠复合凝胶球的制备及其吸附性能研究

利用机械搅拌和超声波辅助法将多壁碳纳米管(MWNTs)分散于海藻酸钠(SA)水溶液中,然后将混合溶液滴入CaCl2水溶液中,制备了具有高吸附性的复合凝胶球(SA/MWNTs-Ca),研究了包埋不同含量MWNTs的SA/MWNTs-Ca凝胶球对甲基橙(MO)溶液的吸附脱色性能.结果表明:SA/MWNTs-Ca凝胶球对甲基...     

Degradation controllable biomaterials constructed from lysozyme-loaded Ca-alginate microparticle/chitosan composites

A degradation controllable composite material was designed to resist the degradation rate variation caused by pH change. The degradation controllable composite materials were prepared by incorporating lysozyme-loaded Ca-alginate microparticles into chitosan matrix. In these materials, the Ca-alginate microparticle carriers can fast release large amount of lysozyme at higher pH to compensate the decrease in enzyme activity, and decrease the release amount at lower pH when lysozyme presents a high activity. Degradation study revealed that the difference among the degradation profiles at various pH values is significantly decreased, indicating an anti-pH-interference effect of the composite films. The result well proved our designing ideas. In addition, the power law and Michaelis equations were used to figure out the inherent relationship between the drug release behavior and the degradation process. Finally, the fluorescence microscopy observation and MTT assay show that the degradation controllable materials have good biocompatibility, which allow adhesion and proliferation of the examined cells.     

Parametric analysis of shape changes of alginate beads

In this article, the various elements controlling the geometry of alginate beads such as voltage, solution concentrations and extrusive rates were experimentally investigated. The findings indicated that the combination of higher voltages more concentrated CaCl₂ solutions, shorter width of electrical field and slower extrusive rates can permit the alginate beads to become smaller. Also the effect of the electrical forces that acted on the liquid droplets was found to be stronger than that of the gravity forces did. The alginate solution concentration was found to influence the beads' shape significantly. Lower concentration of 0.5% resulted in tear-like beads arrangements and a higher concentration of 5 and 8% produced pear-like and sperm-like beads configurations. In addition to obtain special alginate beads, such as elliptical and bullet like beads, outside force could be applied. The above findings could open a broad gate for future control release system developments.