epiglucan and arabinogalactan

Novel polysaccharide hydrogels based on Methocel and beta-glucan or arabinogalactan and corresponding xerogels were prepared and described. Phase stability of hydrogels was confirmed over multiple freeze-thaw cycles. Binary beta-glucan:Methocel hydrogels showed the highest freeze-thaw stability in terms of their syneresis. The viscosity of binary hydrogels was further increased by adding water-soluble resin. Freeze drying of polysaccharide gels yields xerogels suitable as abuse-deterrent vehicles for opioid delivery. The xerogels were characterized by infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, scanning electron microscopy and by their swelling behavior. As a model opioid, tramadol hydrochloride formulations were prepared with various xerogel matrices and dissolution-release profiles were determined. The xerogel matrix acts as a functional excipient that forms a viscous gel barrier with decreased rate of tramadol release. Moreover, slower drug release with no dose dumping is observed in the presence of ethanol. The release kinetics demonstrated that hydrophilic gels with beta-glucan or arabinogalactan are effective for controlling and prolonging the drug release for 12 h which could reduce the required number of administrations.

Topics: Analgesics, Opioid; beta-Glucans; Chemistry, Pharmaceutical; Delayed-Action Preparations; Drug Carriers; Drug Liberation; Excipients; Freeze Drying; Freezing; Galactans; Hydrogels; Kinetics; Polysaccharides; Viscosity; Water

The aim of this work was to evaluate the effects of incorporating thrombin in arabinogalactan (AG)/β-glucan (BG)-based carriers. The products were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray powder diffraction (XRPD) and X-ray photoelectron spectroscopy techniques. Results, especially deconvoluted XRPD patterns indicated creation of new phases and potential complex formation. Results also highlighted that the AG carrier leads to higher residual thrombin-specific activity, while the in vivo haemostatic effect was enhanced when insoluble BG was present in the matrix. Our results confirm that thrombin can be successfully added to the carriers and that these materials are promising alternatives to standard vehicles.

Topics: Animals; beta-Glucans; Drug Carriers; Female; Galactans; Hemostasis; Humans; Male; Microscopy, Electron, Scanning; Particle Size; Photoelectron Spectroscopy; Powder Diffraction; Rats, Wistar; Recombinant Proteins; Spectroscopy, Fourier Transform Infrared; Thrombin; X-Ray Diffraction

Barley endosperm begins development as a syncytium where numerous nuclei line the perimeter of a large vacuolated central cell. Between 3 and 6 days after pollination (DAP) the multinucleate syncytium is cellularized by the centripetal synthesis of cell walls at the interfaces of nuclear cytoplasmic domains between individual nuclei. Here we report the temporal and spatial appearance of key polysaccharides in the cell walls of early developing endosperm of barley, prior to aleurone differentiation. Flowering spikes of barley plants grown under controlled glasshouse conditions were hand-pollinated and the developing grains collected from 3 to 8 DAP. Barley endosperm development was followed at the light and electron microscope levels with monoclonal antibodies specific for (1-->3)-beta-D: -glucan (callose), (1-->3,1-->4)-beta-D: -glucan, hetero-(1-->4)-beta-D: -mannans, arabino-(1-->4)-beta-D: -xylans, arabinogalactan-proteins (AGPs) and with the enzyme, cellobiohydrolase II, to detect (1-->4)-beta-D: -glucan (cellulose). Callose and cellulose were present in the first formed cell walls between 3 and 4 DAP. However, the presence of callose in the endosperm walls was transient and at 6 DAP was only detected in collars surrounding plasmodesmata. (1-->3,1-->4)-beta-D: -Glucan was not deposited in the developing cell walls until approximately 5 DAP and hetero-(1-->4)-beta-D: -mannans followed at 6 DAP. Deposition of AGPs and arabinoxylan in the wall began at 7 and 8 DAP, respectively. For arabinoxylans, there is a possibility that they are deposited earlier in a highly substituted form that is inaccessible to the antibody. Arabinoxylan and heteromannan were also detected in Golgi and associated vesicles in the cytoplasm. In contrast, (1-->3,1-->4)-beta-D: -glucan was not detected in the cytoplasm in endosperm cells; similar results were obtained for coleoptile and suspension cultured cells.

Topics: beta-Glucans; Cell Wall; Cellulose; Galactans; Glucans; Hordeum; Immunohistochemistry; Mannans; Microscopy, Electron, Transmission; Polysaccharides; Seeds; Xylans