Sodium alginate, hydrogel

Two hydrogels of calcium alginate and chitosan-calcium alginate composite were prepared from Na alginate and its composite with chitosan by soaking in O.IM aq. CaCla. A biomimic fixation of aqueous COa - ions as CaCOa was performed. Each of the hydrogels was put into a dialysis membrane tube, and was soaked in 0.1 M aq. NaaCOa (pH 11) at room temperature for 1 day to afford a white precipitate of CaCOa or chitosan-CaCOa and a water-soluble sodium alginate. The dry chitosan-CaCOs composite (60% chitosan and 23% COa -) was stable in aqueous alkaline solutions and unstable in aqueous acidic solutions. 

Another approach to improve the properties of chitosan hydrogels is via the preparation of polymer composites. Porous hydrogels of N-carboxymethyl chitosan/polyvinyl alcohol were prepared by Lee et al. [99]. Hydroxypropyl chitosan was combined with sodium alginate for the formation of biodegradable hydrogels [100]. Chitosan-hyaluronic acid composite was prepared by Tan et al. [101]. 

This vibration system involves a Turbotak air-atomizer in which a pressurized air is injected to mix with the sodium alginate solution. Pressurized air forces the minute liquid droplets out through the orifice of a nozzle and is sprayed into the calcium chloride solution. When these droplets come in contact with calcium chloride solution, calcium ions diffuses into the droplets of sodium alginate, which leads to form microgel droplets. Hydrogel particles thus formed can be further reinforced by poly-L-lysine or chitosan to form a membrane on the droplets. The particle size of hydrogel beads can be obtained in the range of 5 and 15 pm by the use of air atomization technique. ... 

Zhao, S., Cao, M., Li, H., Li, L., Xu, W. Synthesis and characterization of thermosensitive semi-ipn hydrogels based on poly(ethylene glycol)-co-poly(epsilon-caprolactone) macromer, n-isopropylacrylamide, and sodium alginate. Carbohydrate Research 345, 425 31 (2010)... 

Wang Q, Zhang JP, Wang AQ (2009) Preparation and characterization of a novel pH-sensitive chitosan-g-poly (acrylic acid)/attapulgite/sodium alginate composite hydrogel bead for controlled release of diclofenac sodium. Carbohydr Polym 78 731-737... 

HP-y-CD Poloxamer, sodium alginate, HPMC Hydrogels Baicalein Improved stability and mucosa responsive delivery [63]... 

Nagpal Manju, Singh Shailendra Kumar, and Mishra Dinanath. Synthesis characterization and in vitro drug release from acrylamide and sodium alginate based superporous hydrogel devices. Int. J. Pharm. Investig. 3 no. 3 (2013) 131-140. 

The hydrogel has been synthesized by means of free radical polymerization of PVME [1] by y-radiation. A PVME-sodium alginate emulsion was obtained by mixing a 30% (by weight) PVME aqueous solution with a 1% sodium alginate water solution. Then, the emulsion was cross-linked by means of Ca " " ions in a 1M calcium chloride (CaCl2) bath solution and submitted to y-radiation of 0.91 M rad/h for 24 hours. The final PVME hydrogel samples were cut in the form of parallelepiped of various dimensions and left to equilibrate in a bath of de-ionized water at room temperature. 

Dumitriu, R. P, Mitchell, G. R. and Vasile, C. (2011). Multi-responsive hydrogels based on N-isopropylacrylamide and sodium alginate. Polymer International, 60,222-233. 

Kulkarni, R. V., Boppana, R., Mohan, G. K., Mutalik, S. and Kalyane, N. V. (2012). pH-responsive interpenetrating network hydrogel beads of poly(acrylamide)-g-carrageenan and sodium alginate for intestinal targeted drug delivery Synthesis, in vitro and in vivo evaluation. Journal of Colloid and Interface Science, 367,509-517. 

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