Colon-targeting drug delivery systems (CDDSs) are employed to improve the bioavailability of protein and peptide drugs through the oral route. So it is important to prepare the drug carriers for oral CDDS. In this study, the Enzyme-Resistant starch (RS) was studied for use as a vehicle in oral colon-targeting drug delivery. The characteristics of RS powders were investigated by X-ray diffraction, polarizing microscopy, DSC and SEM, and their film were examined by enzymatic digestion test. The results showed that RS could be a promising film-former for pharmaceutical coatings, having good stability to enzymatic digestion. Furthermore, a novel peroral formulation using RS coating and bovine serum albumin as a model drug was studied for colon-specific drug delivery in vitro. Drug release studies have shown that RS coating could delivery the drug to the colon and the release rate in simulated colonic fluids was dependent on the biodegradation of RS and its coatings. It is indicated that the RS coated tablet is a potential system for oral CDDS.

The process, thermodynamical isotherm and mechanism of Cr(III) uptake by Spirulina platensis were investigated in this paper. At the beginning of Cr uptake, Cr is physically adsorbed to the surface of algal cell by electrostatic attraction. Finally, chemical complexation through ion-exchange with K+, Mn2+, Ca2+, Mg2+, Na+, Fe3+, Zn2+, H+, etc. ions by reversible or irreversible strategies plays the main role in Cr uptake. Most of the absorbed Cr are steadily bound to proteins, polysaccharides, lipids, etc. Biological ligands, whereas only a very small part of Cr are loosely adsorbed on the algal surface. Langmuir isotherm model seems to be suitable for describing Cr uptake than Freundlich isotherm model. pH is the most important factor influencing Cr uptake as well as anions, cell concentration, Cr concentration, temperature, light. Scatchard analysis and isotherm analysis indicate multi types binding sites for Cr and multi interactions between Cr and alga. Bioaccumulation strategy is suggested to be involved in Cr uptake besides biosorption e.g. adsorption and chemical complexation. S. platensis is of efficiently capable in the uptake of Cr(III), consequently high-value Spirulina can be produced.

Abstract: The objective of the study was to evaluate the effect of a novel biodegradable membrane on the prevention of postoperative adhesion formation. The membrane was prepared by blending 50% PLA (polylactic acid) with 50% PTMC (polytrimethylene carbonate). The prepared blends polymer membrane was more flexible than pure PLA membrane, as measured by glass-transition temperature and tensile study. Cytotoxicity study revealed that PLA/PTMC blends membrane showed good biocompatibility. The membrane elicited slight tissue reaction based on the results of histological study. Thirty adult Japanese rabbits were used for the intestine adhesion model. The treatment group had PLA/PTMC membrane, the control group had chitosan, and the blank control group was not operated. The animals were housed for two weeks and sacrificed to investigate adhesion of intestine. Compared with the blank control group, the treatment group and the control group lowered the extent of adhesions (p < 0.01), but the treatment group was better than the control group (p < 0.05). The in-vivo studies confirmed that PLA/PTMC blends membrane could prevent postoperative adhesions.

The influence of covalent cross-linking by microbial transglutaminase (MTGase) on the sequential in vitro pepsin and trypsin digestion process and the digestibility of soy protein isolate (SPI), was investigated by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and nitrogen release analyses. Various subunits of b-conglycinin and acidic subunits of glycinin were cross-linked by MTGase to form high molecular weight (MW) biopolymers, while basic subunits of glycinin were unaffected. SDS-PAGE analysis indicated that the cross-linking mainly affected in vitro pepsin digestion pattern of various subunits of b-conglycinin, while the trypsin digestion pattern of native SPI was nearly unaffected. Nitrogen release analysis showed that the in vitro pepsin or/and trypsin digestibility of native SPI (at the end of pepsin or trypsin ingestion) was significantly decreased (P＞0.01) by the MTGase treatment (for more than 2 h). The cross-linking by MTGase also significantly decreased the in vitro digestibility of preheated SPI. These results suggest that the cross-linking by means of transglutaminase may negatively affect the nutritional properties of food proteins.

The eVects of covalent cross-linking of microbial transglutaminase (MTGase) on the thermal properties of soy protein isolates (SPI), including the thermal denaturation and glass transition were investigated by conventional and modulated diverential scanning calorimetry (DSC). The MTGase treatment signiWcantly increased the thermal denaturation temperatures (including the on-set temperature of denaturation, Tm and the peak temperature of denaturation, Td) of glycinin and-conglycinin components of SPI (P60.05), and the thermal pretreatment of SPI further increased the extent of this improvement. The MTGase treatment also improved the ability of SPI to resist the urea-induced denaturation. Modulated DSC analysis showed that there were two glass transition temperatures (Tg) in the reversible heat Xow signals of native SPI (about 5% moisture content), approximately corresponding to 45 and 180