Jani Trygg

Physicochemical design of the morphology and ultrastructure of cellulose beads

Cellulose was dissolved in NaOH-urea-water and beads were prepared by coagulation into nitric acid as well as saline solution. Morphology and ultrastructure of the beads were modified by controlling the molarity of the acid (0-10M) and temperature (5-50°C) of the coagulation media and the cellulose concentration (3-7%). The beads were characterized by optical image analysis (shape, volume, and size distribution) and weight (total porosity). Cross-sections of CO2 critical point dried beads were studied by field emission scanning electron microscopy (FE-SEM) and specific surface areas of 336-470m(2)g(-1) were determined from nitrogen adsorption isoterms. Pore size distribution was analyzed using solute exclusion technique. Our results demonstrate that the ultrastructure can be controlled by alteration of the coagulation conditions. Changes in size, shape and surface area were substential. Also generation of micro- (⩽2Å), meso-, or macropores (⩾50Å) can be favored.

Synthesis of novel zwitterionic cellulose beads by oxidation and coupling chemistry in water

The design and synthesis of polysaccharide-based materials utilizing a systematic approach is essential to develop sustainable and biodegradable value added products. In this work, new zwitterionic cellulose beads of desired size range were prepared via spin drop atomization followed by sol gel transition technique. Carboxylic acid (COOH) and carbonyl (C=O) moieties were generated using NaClO2/NaClO/TEMPO mediated oxidation system under heterogenous reaction conditions. Coupling reaction between carboxymethyl trimethylammonium chloride hydrazide (Girard’s reagent T) and carbonyl functionalities on cellulose resulted in the formation of stable hydrazone groups. A variation in molar ratio of NaClO2, NaClO and TEMPO were studied to understand the effect of each reagent on the generation of oxidized products. COOH and C=O content was determined by conductometric titrations and oximation with hydroxylamine hydrochloride followed by elemental analysis, respectively. Evidence of functionalization was obtained with ATR-FTIR, Raman, solid state 13C NMR spectroscopic studies and ToF–SIMS analysis. Morphological changes were studied by FE-SEM. The increased porosity and hydrophilicity of zwitterionic beads provides a platform for the future application of these beads in separation of biomolecules, chiral molecules, immobilization of proteins and enzymes and encapsulation of zwitterionic drugs.

Investigation of dissolved cellulose in development of buccal discs for oromucosal drug delivery

Abstract Mucoadhesive formulations have a wide scope of application for both systemic and local treatment of various diseases. In the case of recurrent aphthous stomatitis, to ensure effective therapy, the concentration of corticosteroids, and/or anesthetics at the mouth ulcer side should be maintained with minimal systemic absorption. Therefore, the aim of the study was to investigate cellulose-based formulations, in achieving suitable hardness, mucoadhesiveness, and sustained release of the active ingredients directed towards the mucosa for an extended period of time (∼4 h). This was examined by creating polymer reinforced cellulose composites which consisted of porous cellulose discs (CD) and different polymer components namely polyethylene glycol 6000 (PEG6000), polyethylene glycol 400 (PEG400), and ethyl cellulose. Empty CDs were formed by dropping dissolved cellulose into coagulation medium. The empty porous CDs were immersed into different drug loading solutions which were prepared by dissolving three different concentrations of triamcinolone acetonide and lidocaine hydrochloride in five different ratios of PEG 6000:PEG 400:ethanol (w:w:w %) solutions. All formulations were investigated regarding drug content, release, hardness, and mucoadhesive properties. The results indicate that the non-dispersing buccal discs had sufficient hardness, drug content and in vitro release properties, but further studies are needed to achieve proper mucoadhesiveness.