Preparation of Chitin-g-poly(4-vinylpyridine) Beads

Pectin/lignocellulose nanofibers/chitin nanofibers bionanocomposite as an efficient biosorbent of cholesterol and bile salts

A new biosorbent Ca-crosslinked pectin/lignocellulose nanofibers/chitin nanofibers (PLCN) was synthesized for cholesterol and bile salts adsorption from simulated intestinal fluid during gastric-intestinal passage. The physico-chemical properties of PLCN were studied using SEM, FTIR, XRD, DSC and BET. Before gastrointestinal passage, PLCN had an amorphous single-phase, compact structure formed via hydrogen and van der Waals bonds that revealed an irregular shape with the shriveled surface but watery condition and enzymatic digestion led to create a porous structure without destruction because of the water-insoluble nanofibers, therefore increasing the adsorption capacity. The maximum adsorption capacity reached 37.9 and 5578.4 mg/g for cholesterol and bile salts, respectively. Freundlich isotherm model indicated the reversible heterogeneous adsorption of both cholesterol and bile salts on PLCN. Further, their adsorption followed pseudo-second order kinetic model. These results suggest that PLCN has potential as a gastrointestinal-resistant biosorbent for cholesterol and bile salts adsorption applicable in medicine and food industry.

Preparation and analysis of photochromic behavior of carboxymethyl chitin derivatives containing spiropyran moieties

1ʹ-(2-Acryloxyethyl)-3,3ʹ-dimethyl-6-nitrospiro[2 H-1-benzopyran-2,2ʹ-indoline] (SPA) was synthesized and grafted onto a water-soluble carboxymethyl chitin (CMCH) macromolecule to prepare a photochromic copolymer (CMCH-g-SPA). The structure of CMCH-g-SPA was characterized by Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric (TG) analysis, X-ray diffraction (XRD) analysis, water-solubility evaluation, and UV-vis spectroscopy. XRD patterns of CMCH-g-SPA revealed that grafting copolymerization disrupts the CMCH semicrystalline structure, thus improving water solubility. UV-vis spectroscopy results supported the negative photochromic behavior of the merocyanine (MC) form of CMCH-g-SPA (CMCH-g-MCA) present in a water solution of the target copolymer. In addition to high solvent polarity, the intermolecular and intramolecular electrostatic attraction between the indolenine cation and the COO⁻ anion were found to be influencing factors, which stabilize these MC form of spiropyran groups grafted onto CMCH. In a water solution, visible light bleaching was completed over a short period (8 minutes) under artificial visible light irradiation and the thermal coloration reaction, whose rate constant at 25 °C was 4.64 × 10⁻⁴ s⁻¹, which fit the first-order reaction equation. After ten photochromic cycles in water solution, the relative absorption intensity of CMCH-g-MCA decreased by 7.92%.

Technologies and Formulation Design of Polysaccharide-Based Hydrogels for Drug Delivery

Polysaccharide-based hydrogel particles (PbHPs) are very promising carriers aiming to control and target the release of drugs with different physico-chemical properties. Such delivery systems can offer benefits through the proper encapsulation of many drugs (non-steroidal and steroidal anti-inflammatory drugs, antibiotics, etc) ensuring their proper release and targeting. This review discusses the different phases involved in the production of PbHPs in pharmaceutical technology, such as droplet formation (SOL phase), sol-gel transition of the droplets (GEL phase) and drying, as well as the different methods available for droplet production with a special focus on prilling technique. In addition, an overview of the various droplet gelation methods with particular emphasis on ionic cross-linking of several polysaccharides enabling the formation of particles with inner highly porous network or nanofibrillar structure is given. Moreover, a detailed survey of the different inner texture, in xerogels, cryogels or aerogels, each with specific arrangement and properties, which can be obtained with different drying methods, is presented. Various case studies are reported to highlight the most appropriate application of such systems in pharmaceutical field. We also describe the challenges to be faced for the breakthrough towards clinic studies and, finally, the market, focusing on the useful approach of safety-by-design (SbD).

Review on the Production of Polysaccharide Aerogel Particles

A detailed study of the production of polysaccharide aerogel (bio-aerogel) particles from lab to pilot scale is surveyed in this article. An introduction to various droplets techniques available in the market is given and compared with the lab scale production of droplets using pipettes and syringes. An overview of the mechanisms of gelation of polysaccharide solutions together with non-solvent induced phase separation option is then discussed in the view of making wet particles. The main steps of particle recovery and solvent exchange are briefly described in order to pass through the final drying process. Various drying processes are overviewed and the importance of supercritical drying is highlighted. In addition, we present the characterization techniques to analyse the morphology and properties of the aerogels. The case studies of bio-aerogel (agar, alginate, cellulose, chitin, κ-carrageenan, pectin and starch) particles are reviewed. Potential applications of polysaccharide aerogel particles are briefly given. Finally, the conclusions summarize the prospects of the potential scale-up methods for producing bio-aerogel particles.