Controlling plasticizer migration based on crystal structure and micromorphology in propionylated starch-based food packaging nanocomposites.

Migration of additives is an important issue for proper application in food packaging. In this work, propionylated waxy and normal starch-based nanocomposites (PW-N and PN-N) with two different amylopectin content were immersed in distilled water, and structural changes and migration mechanism of plasticizer (triacetin) were discussed in detail. Results showed that when immersion time was prolonged to 150 h, small crystals of PN-N disappeared, and amorphous structures formed gradually in PW-N and PN-N. Exfoliated structures still remained in PW-N with prolonged immersion time, while exfoliated structures gradually formed from intercalated ones in PN-N, and the peak representing d001 (d-spacing) at q = 1.70 nm-1 faded. The migration mechanism of triacetin obeyed the first-order kinetic model and Fick's law; furthermore, in comparison with PW-N, PN-N showed a larger diffusion coefficient (D2 = 12.13 µm2·h-1). These results contributed to expanding the application of starch-based nanocomposites in future environmentally friendly food packaging.

Bioequivalence decision for nanoparticular iron complex drugs for parenteral administration based on their disposition.

Although parenteral iron products have been established to medicinal use decades before, their structure and pharmacokinetic properties are not fully characterized yet. With its' second reflection paper on intravenous iron-based nano-colloidal products (EMA/CHMP/SWP/620008/2012) the European Medicine Agency provided an extensive catalogue of methods for quality, non-clinical and pharmacokinetic studies for the comparison of nano-sized iron products to an originator (EMA, 2015). For iron distribution studies, the reflection paper assumed the use of rodents. In our tests, we used a turkey fetus model to investigate time dependent tissue concentrations in pharmacological and toxicological relevant tissues liver, heart and kidney. We found turkey embryos to be a suitable alternative to rodents with high discriminatory sensitivity. Clear differences were found between equimolar doses of iron products with hydroxyethyl amylopectin, sucrose, dextrane and carboxymaltose shell. A linear dose dependency for the tissue accumulation was also demonstrated.

Amylopectin-g-poly(methylacrylate-co-sodium acrylate): An efficient Cd(II) binder.

Synthesis, characterization and Cd(II) adsorption studies of a novel biodegradable graft copolymer based on partially hydrolysed polymethylacrylate (PMA) grafted amylopectin was reported, which was prepared by first grafting of PMA chains onto the amylopectin backbone followed by partial alkaline hydrolysis. The hydrolysed graft copolymer (PHAP) was characterized by measuring saponification equivalent (SE), FTIR, (1)H NMR and (13)C NMR spectroscopy and thermal analysis (TG/DTG). The graft copolymer was biodegradable. Various operating variables affecting the metal sorption such as, amount of adsorbent, solution pH, contact time, temperature and Cd(II) solution concentration were studied which showed that the maximum adsorption of Cd(II) was found at pH 5.5, temperature 90°C, time 120min, polymer dose, 0.02g/L and initial Cd(II) concentration, 50mg/L. The adsorption data were well described by the pseudo-second-order and Langmuir isotherm model. Metal complexation studies were carried out experimentally using UV-visible, FTIR spectroscopy and theoretically using Density Functional Theory by Gaussian 09 and Gauss view 5.0 programmes which confirms a square planer geometry involving Cd(II) and COO(-) groups. Calculation of the various thermodynamic parameters was also done. The negative value of free energy change indicates the spontaneous nature of the adsorption.

Combined application of polyacrylate scaffold and lipoic acid treatment promotes neural tissue reparation after brain injury.

PRIMARY OBJECTIVE: The aim of this study was to investigate the reparative potential of a polymeric scaffold designed for brain tissue repair in combination with lipoic acid. RESEARCH DESIGN: Histological, cytological and structural analysis of a combined treatment after a brain cryo-injury model in rats. METHODS AND PROCEDURES: Adult Wistar rats were subjected to cryogenic brain injury. A channelled-porous scaffold of ethyl acrylate and hydroxyethylacrylate, p(EA-co-HEA) was grafted into cerebral penumbra alone or combined with intraperitoneal LA administration. Histological and cytological evaluation was performed after 15 and 60 days and structural magnetic resonance (MRI) assessment was performed at 2 and 6 months after the surgery. MAIN OUTCOMES AND RESULTS: The scaffold was suitable for the establishment of different cellular types. The results obtained suggest that this strategy promotes blood vessels formation, decreased microglial response and neuron migration, particularly when LA was administrated. CONCLUSIONS: These evidences demonstrated that the combination of a channelled polymer scaffold with LA administration may represent a potential treatment for neural tissue repair after brain injury.

Synthesis, characterization and application of novel cationic and amphoteric flocculants based on amylopectin.

The synthesis of novel cationic flocculants based on amylopectin (AP), acrylamide (AM) and (3-acrylamidopropyl) trimethylammonium chloride (ATMAC) were done by free radical polymerization using ammonium persulphate (APS) as an initiator. Three different grades of novel cationic flocculants (AP-g-C 1 to AP-g-C 3) were synthesized by varying the proportion of acrylamide and (3-acrylamidopropyl) trimethylammonium chloride monomers. Through the hydrolysis of these flocculants, in presence of NaOH, three different grades of amphoteric polymers (AP-AT-C 1 to AP-AT-C 3) were synthesized. The synthesized polymers were characterized by various methods, namely, infrared spectroscopy, NMR spectroscopy, thermal analysis, viscosity measurement, scanning electron microscopy and X-ray diffractometry. The flocculation performance of AP-g-C and AP-AT-C were studied in kaolin suspension using jar test and settling test methods at neutral pH. Dye (Methylene blue) removal tests were performed using polymer beads and analysed by UV-vis spectroscopy.

Analysis of the functional interaction of Arabidopsis starch synthase and branching enzyme isoforms reveals that the cooperative action of SSI and BEs results in glucans with polymodal chain length distribution similar to amylopectin.

Starch synthase (SS) and branching enzyme (BE) establish the two glycosidic linkages existing in starch. Both enzymes exist as several isoforms. Enzymes derived from several species were studied extensively both in vivo and in vitro over the last years, however, analyses of a functional interaction of SS and BE isoforms are missing so far. Here, we present data from in vitro studies including both interaction of leaf derived and heterologously expressed SS and BE isoforms. We found that SSI activity in native PAGE without addition of glucans was dependent on at least one of the two BE isoforms active in Arabidopsis leaves. This interaction is most likely not based on a physical association of the enzymes, as demonstrated by immunodetection and native PAGE mobility analysis of SSI, BE2, and BE3. The glucans formed by the action of SSI/BEs were analysed using leaf protein extracts from wild type and be single mutants (Atbe2 and Atbe3 mutant lines) and by different combinations of recombinant proteins. Chain length distribution (CLD) patterns of the formed glucans were irrespective of SSI and BE isoforms origin and still independent of assay conditions. Furthermore, we show that all SS isoforms (SSI-SSIV) were able to interact with BEs and form branched glucans. However, only SSI/BEs generated a polymodal distribution of glucans which was similar to CLD pattern detected in amylopectin of Arabidopsis leaf starch. We discuss the impact of the SSI/BEs interplay for the CLD pattern of amylopectin.

One-step synthesis of amphiphilic hyperbranched amylopectin derivatives, characterization and use as functional nanovehicles.

Amylopectin is a naturally hyperbranched biopolymer with an extremely high molecular weight. Furthermore, this material is non-toxic in nature, and exhibits good biocompatibility and biodegradability properties. Herein, we describe the development of a one-step reaction strategy for the synthesis of amphiphilic high-molecular-weight hyperbranched amylopectin derivatives with hydrophobic shells and large hydrophilic cores. The chemical structures of the resulting materials were characterized using FTIR spectroscopy, solid-state (13)C cross-polarization/magic angle spinning NMR spectroscopy and gas chromatography. The results from transmission electron microscopy, fluorescence spectroscopy, and UV-vis analysis confirmed that the hyperbranched amylopectin derivatives were composed of hydrophobic shells with cholesteryl residues and hydrophilic amylopectin cores. These amylopectin derivatives exhibited high encapsulation capabilities toward water-soluble molecules, and could be used as functional nanovehicles for the controlled release of water-soluble molecules, and the in situ synthesis of metallic nanoparticles.

Preparation and characterization of new and improved soluble-starches, -amylose, and -amylopectin by reaction with benzaldehyde/zinc chloride.

Seven different starches from potato, rice, maize, waxymaize, amylomaize-VII, shoti, and tapioca, and potato amylose and potato amylopectin have been reacted with benzaldehyde, catalyzed by ZnCl(2), to give new water-soluble starches and water soluble-amylose and soluble-amylopectin. In contrast to the native starches, aqueous solutions of the modified starches could not be precipitated with 2-, 3-, or 4-volumes of ethanol. ß-Amylase gave no reaction with the modified starches, in contrast to the native starches, indicating that the modification occurred exclusively at the nonreducing-ends, giving 4,6-benzylidene-D-glucopyranose at the nonreducing-ends. Reactions of α-amylase with native and modified potato and rice starches gave a decrease in the triiodide blue color and an increase in the reducing-value that were similar for the native- and modified-starches, indicating the modified starches had not been significantly altered by the modification. The benzaldehyde-modified starches and benzaldehyde-modified potato amylose and potato amylopectin components, therefore, have a starch structure very much like their native counterparts, in contrast to the Lintner, Small, and the alcohol/acid-hydrolyzed soluble-starches that have undergone acid hydrolysis. The benzaldehyde-modified starches and starch components have significantly higher water solubility than their native counterparts even though the structures of the modified starches had only been slightly altered from the structures of their native counterparts. They all gave crystal-clear solutions that did not retrograde.

Synthesis of triazole-linked pseudo-starch fragments.

Rapid assembly of starch fragment analogues was achieved using 'click chemistry'. Specifically, a pentadecasaccharide and two hexadecasaccharide mimics containing two parallel maltoheptaosyl chains linked via [1,2,3]-triazoles to glucose or maltose core were synthesised using Cu(I)-catalyzed [3+2] dipolar cycloaddition of azidosaccharides and 4,6-di-O-propargylated methyl alpha-d-glucopyranoside and 6,6'- and 4',6'-di-O-propargylated p-methoxyphenyl beta-maltoside.

[Preparation of amylopectin modified dipyridamole liposome and its tissue distribution in mice].

AIM: To prepare amylopectin anchored dipyridamole (DIP) liposome and to study its tissue distribution in mice. METHODS: The regular DIP liposomes were prepared by film-scatter method. The amphiphilic O-palmitoyl amylopectin was synthesized and added to modify the surface of liposome. The entrapping efficiency, zeta potential, mean diameter, span of modified and regular liposomes were assayed. The RP-HPLC was used for the determination of DIP concentration in mice tissue. RESULTS: After modification, the entrapping efficiency depressed, zeta potential was raised, mean diameter and span had no obvious change. The level of DIP in lung, liver and spleen for regular liposomes were higher than that of injections. Compared with regular liposomes, the modified liposomes increased the DIP level in lung, and decreased the DIP level in liver, spleen, moreover, lengthened the retention time of DIP in lung. CONCLUSION: The distribution of modified liposome in mice was markedly changed as compared with regular liposomes and injections. The modified liposomes had obvious lung targeting property.

Cationic amylopectin derivatives as additives for analysis of proteins in capillary electrophoresis.

Positively charged amylopectin, which is a major constituent of cationic starch, was used to modify the inner surface of fused-silica capillaries by addition to the running solution, which was subsequently employed in CE. Capillaries filled with cationic amylopectin derivatives were shown to generate a stable reversed EOF in the investigated range of pH 4-8. Among the additives studied, quaternary ammonium amylopectin derivatives with high amino and low hydroxypropyl groups showed fast electroosmotic mobility and very effectively suppressed the adsorption of proteins. The run-to-run and batch-to-batch repeatability of the procedures were satisfactory with RSDs of 0.5% and 2.4%, respectively. A basic protein, alpha-chymotrypsinogen, migrated within 6 min and the theoretical plate number of it reached 560 000 plates/m.

Stability and pharmacokinetic studies of O-palmitoyl amylopectin anchored dipyridamole liposomes.

Modified polysaccharides have been used widely to increase physico-chemical stability of liposomes. However, the stability and pharmacokinetic studies on the polysaccharides modified anchored liposomes containing hydrophobic drugs which exist in lipid bilayer membranes were insufficient as compared with the liposomes carrying hydrophilic or ionic drugs in inner aqueous phase. In the present study, a hydrophobic drug, dipyridamole (DIP), was entrapped into liposomes through film hydration. Amylopectin was palmitoylated and anchored on the surface of plain DIP liposomes. Subsequently, the stabilities of DIP ethanol solution, plain DIP liposomes (PDL) and anchored DIP liposomes (ODL) against irradiation, disperse medium, biofluid, long-term storage were determined and compared. The concentrations of DIP in plasma of rats and its pharmacokinetic behaviors after intravenous administration of DIP injection, PDL and ODL were studied by RP-HPLC. The pharmacokinetic parameters were computed by software 3p97 programme. The results showed that ODL could increase stabilities more of DIP in vitro as compared with PDL. The plasma concentration-time curves of DIP after intravenous administration of DIP injection, PDL and ODL were all in accordance with open two-compartment model. Pharmacokinetic parameters of DIP injection, PDL and ODL in rats were significantly different. The present findings suggest that anchored liposomes could increase stabilities of DIP in vitro as compared with plain liposomes. Furthermore, the difference of pharmacokinetic profiles was due to the targetability of anchored liposomes.

Basic features of hypoxic pulmonary vasoconstriction in mice.

Hypoxic pulmonary vasoconstriction (HPV) matches lung perfusion with ventilation which tends to optimize pulmonary gas exchange. Investigations using genetically engineered mice represent a promising approach to understand the underlying mechanisms. Our goal was to characterize basic features of HPV in the isolated buffer-perfused and ventilated mouse lung system. HPV was reproducible for several hours when ventilating the lungs with 1% O2 (10 min) alternated with normoxic ventilation periods (21% O2, 15 min). HPV was well elicitable and most constant using Krebs-Henseleit buffer with the addition of hydroxyethylamylopectin as an oncotic agent. Inhibition of both lung NO and prostanoid formation amplified HPV in an over-additive fashion. HPV was higher in BALB/c mive as compared to C57BL/6 mice, and was approximately threefold enhanced under positive pressure ventilation as compared to negative pressure ventilation. A three hour hypoxic ventilation period resulted in a biphasic vasoconstrictor response with loss of posthypoxic vasodilatation. In summary, we have characterised HPV and established an experimental set-up optimized for investigation of the basic mechanisms of HPV in mice.

The catabolism of low molecular weight-hydroxyethylated amylopectin in man. III. Further degradation of excreted polymer fragments.

Fragments of low molecular weight-hydroxyethylated amylopectin (LMW-HES) contained in the urine voided by a single normal man, 6 to 12 hours after receiving a dose of 56 g of this material, were either separated straightforwardly by gel filtration on a column of Sephadex G-200 or incubated for 18 hours at 37 degrees C in the presence of alpha-amylase contained in human saliva, and then subjected to filtration on the same column. Comparison of the two elution profiles revealed that LMW-HES material remaining in the bloodstream for 6-hours or more, had not been degraded by serum alpha-amylase to the maximum possible extent, since incubation with alpha-amylase in-vitro caused further catabolism. These data suggest that LMW-HES polymer fragments are excreted in the urine as soon as they obtain a molecular weight below the threshold of glomerular filtration.

Catabolism of low-molecular-weight hydroxyethylated amylopectin in man. I. Changes in the circulating molecular composition.

Intravascular persistence concomitant with changes in the circulating molecular composition were determined in six fasted normal men dosed with 400 ml of 14% LMW-HES (a new plasma expander). The concentration of LMW-HES in serum fell to half its peak value in 3.9 +/- 1.1 (S.D.) hr, whereas serum levels of glucose remained elevated throughout the 12 hr postinjection fasting period. The LMW-HES recovered from the intravascular space was shown by gel filtration on a column of Sepharose CL-4B to be a narrower molecular size distribution (less polydispersion) than the injected material. The ratio of Kav . urine/Kav . injected solution was 1.34. At 30 min after injection, however, the ratio of Kav . urine/Kav . serum was 1.20, and by 24 hr, the value was 1.15. Overall, changes in the molecular distribution in the bloodstream between the end of the infusion period and 24 hr later were small. The results suggest that the intravascular catabolism of LMW-HES may occur in two distinct phases: a rapid initial degradation, followed by a more gradual elimination influenced by the MS of the injected material.

Transfusion of hydroxyethylated amylopectin-protected frozen blood in man. I. Plasma clearance and renal excretion of the cryoprotectant.

In man following the autologous transfusion of blood previously frozen with 14% low molecular weight-hydroxyethylated amylopectin (cryo-HES), the clearance of this material from the intravascular space was compound, and appeared to consist of exponential components. The overall half-life -- however, was 10.6 +/- 3.0 (SD) h. Approximately 17% of the total infused cryo-HES was excreted in the urine 1 h postinjection, and 40% by 72 h. The erythrocyte sedimentation rate (ESR) was not affected by the presence of this substance in the bloodstream of the recipient. The results indicate that cryo-HES is removed rapidly following the transfusion of blood previously frozen with this material.

Plasma clearance and renal excretion of erythrocyte cryoprotectant hydroxyethylated amylopectin.

The value of low molecular weight-hydroxyethylated amylopectin (cryo-HES) as an extracellular cryoprotectant has been demonstrated in vitro. It is important that details of the intravascular persistence and urinary excretion be determined to compare with data already available as other grades of HES and with data on transfusion of cryo-HES cryoprotected blood. Following a single 400 ml (14% solution) infusion in man, the intravascular clearance of cryo-HES was well described mathematically by the equation: y = 3.30+6.49e-0.15kappa. The plasma concentration of cryo-HES fell to half its peak value in approximately 9.6 h. Approximately 20% of the total infused cryo-HES was excreted in the urine during the first post-injection hour, and 50% by 72 h. The ESR was not altered significantly by the presence of this material. The present study indicates that cryo-HES is eliminated rapidly and may thus be safe for transfusion to recipients of frozen blood.