Search

Carboxymethyl κ-carrageenan (CMκC)/alginate (AL) blend fibers were prepared by spinning their mixture solution through a viscose-type spinneret into a coagulating bath containing aqueous CaCl2 and ethanol. The structure and properties of blend fibers were studied with the aid of infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis. The analyses indicated a good miscibility between AL and CMκC because of the strong interaction of the intermolecular hydrogen bonds. The mechanical properties and water-retention properties were also measured. The best values of tensile strength and breaking elongation were obtained when CMκC content was 30 wt.%. The water-retention properties and thermostability improved by blending method. Antibacterial fibers, obtained by the treatment of the fibers with an aqueous solution of silver nitrate, exhibited good antibacterial activity to Staphylococcus aureus.

Cationic polymers have been widely used as drug delivery systems. Herein, an oxidized sodium alginate/chitosan (OSA/CS) core-shell microgel was prepared via water-in-oil emulsion method. Morphological properties of the resulting microgel were determined by transmission electron microscopy, hydrodynamic diameter of the microgel was characterized by dynamic light scattering. The objective of this work was to achieve the colon-specific delivery of an antiulcerative colitis drug using a fully nontoxic carrier. 5-aminosalicylic acid (5-ASA) was chosen as a model drug, which is rapidly absorbed before entering the colon, thus it is necessary to develop a colon-specific delivery system for it. The in vitro drug release profile was established in buffer solutions with 0.1 M HCl/NaCl (pH 1.2) and 0.1 M phosphate buffered saline (pH 7.4) at 37 °C. The results indicated that this OSA/CS core-shell microgel inhibited the release of 5-ASA in stomach to a certain extent and is degradable in physiological conditions. Due to the excellent biocompatible nature of CS and OSA, this core-shell microgel has good biocompatibility and may have potential applications in oral controlled drug delivery systems.

Aerogels of natural polysaccharides possess both biocharacteristics of polysaccharides, such as good biological compatibility and cell or enzyme-controlled degradability, and aerogel characteristics, such as very high porosity and specific surface areas that makes them highly attractive in drug delivery. Biodegradable alginate aerogels were synthesized via a sol-gel process. In the present work two methods of ionic cross-linking were used to prepare alginate hydrogels as monoliths and spheres, which can be further easily converted to high surface area aerogels. The aerogels obtained were further used as drug carriers. We investigated the effect of process parameters, such as starting concentration and viscosity of alginate solution, on synthesis products and on model drug (nicotinic acid) release. The results indicate that by using the internal setting cross-linking method for obtaining monolithic aerogels nicotinic acid was released in a more controlled manner. The aerogels thus obtained also exhibited smaller volume shrinkage than the ones described in other publications. However, with increasing alginate concentration in both types of synthesis more compact and cross-linked aerogels were formed.

Macromolecularly imprinted polymers have been developed to mimic the non-covalent interactions driving molecular recognition in nature. The creation of an engineered antibody mimic would allow for the development of customizable films for biomolecular sensing. To demonstrate this principle, a cross-linked alginate film has been imprinted with bovine serum albumin (BSA) using aqueous biocompatible gelation methods. The imprinting efficiency of the synthesized films imprinted with BSA was determined and compared to the non-specific uptake of complementary proteins which were not imprinted in the alginate matrix. It was found that the recognition of the BSA using an alginate film was 6.4 mg/g polymer, which compares favorably to previously reported macromolecularly imprinted networks. The absorption of non-imprinted cationic proteins by the alginate matrix demonstrates that overcoming non-specific binding needs to be a focus of future work in order to successfully employ these materials towards biomolecular sensing within a physiological environment.

The aim of this work was to evaluate the feasibility and efficacy of flexible adhesive electrodes (FAEs) prepared with adhesive matrices for iontophoretic delivery of baicalin, a drug used for the treatment of atopic dermatitis, viral hepatitis and HIV. Single-layer adhesive matrices (SLAMs) and double-layer adhesive matrices (DLAMs) were prepared from carbomer 940, sodium alginate and polyvinyl alcohol with appropriate mechanical and high baicalin release properties. During the direct-current (DC) iontophoresis with SLAM FAEs, electrochemical reaction caused a clear decrease of pH value at the interface IF(+,FCL) and an increase of pH value at the interface IF(-,FCL). An additional pH-controlling layer in DLAMs could adjust the pH value of interfaces. Thus, deterioration of baicalin stability and the competitive delivery of hydroxyl ions produced with baicalin anions would be avoided during iontophoresis. Iontophoretic flux of baicalin from a DLAM FAE cathode increased proportionally to the time from the onset and affected by the current density and the frequency of pulsed DC. Increasing the applied current or the frequency could enhance the skin permeation flux of baicalin. Moreover, the baicalin skin permeation flux could be further improved from 0.22 microg/cm(2) per h in iontophoresis alone to 0.43 microg/cm(2) per h in the combined approach of iontophoresis and Azone.