Calcium alginate Chitosan

Bajpai SK, Ihnkhiwale R. [2006]. Investigation of water uptake behavior and stability of calcium alginate/chitosan bi-polymeric beads Part-1. React Fund Polym, 66,645-658. 

Pasparakis G, Bouropoulos N. (2006). Swelling studies and in vitro release of verapamil from calcium alginate and calcium alginate-chitosan beads International.y Pharm, 323,34-42. 

The majority of the aforementioned capsules were either not sufficiently mechanically stable or suffered from other surface or matrix related deficiencies. These deficiencies include poor morphology, such as capsule sphericity and surface smoothness, which result from an osmolar imbalance. Membranes are also often leaky (an internal polymer slowly diffuses out through the capsule wall) or shrink in either PBS or in culture media over a period of a few hours. Exceptionally, some capsules are observed to swell excessively and burst. Furthermore, some complex membranes, although stable in water, dissolve over several days upon a contact with culture media. This is true for pectin based capsules (pectin/calcium salt) and for alginate-chitosan membranes and maybe a consequence of the polycation substitution by electrolytes present in the media [10]. In order to improve the existing binary capsules several approaches, both traditional and novel, have been considered and tested herein. These are discussed in the following sections. 

Peniche, C., Howland, I., Carrillo, O., Zaldivar, C., Argqelles-Monal, W. (2004). Formation and stability of shark liver oil loaded chitosan/calcium alginate capsules. FoodHy-drocolloids, 18, 865-871. 

Similarly, the encapsulation of various molecules (BSA and dextrans with various molecular weights) in calcium alginate beads coated with chitosan has been reported [178,179]. Their release has been compared and the influence of the conformation, the chemical composition and the molecular weight of the encapsulated materials has been analyzed [178]. The ionic interactions between alginate and chitosan at different pH values are depicted in Fig. 10. 

Lee, J.S., Cha, D.S., and Park, H.J. (2004). Survival of freeze-dried Lactobacillus bulgaricus KFRI 673 in chitosan-coated calcium alginate microparticles. J. Agric. Food Chem. 52, 7300-7305. 

Alginate-poly(L-lysine) and alginate-chitosan are, by far, the most common polymer-polymer coacer-vation systems, with the former often pregelled, in bead form, with divalent cations such as calcium or barium. As Table 2 indicates, polysaccharides with a rigid structure are generally favored for polysalt formation. 

Gaserod O, Jolliffe IG, Hampson FC, Dettmar PW, Skjak-Braek G. Enhancement of the bioadhesive properties of calcium alginate gel beads by coating with chitosan. Int J Pharm 1998 175 237-246. 

Biomimetic mineralization of aqueous carbonate ions into chitosan-calcium alginate hydrogels... 

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. 

Peng P et al (2008) Concurrent elution of calcium phosphate and macromolecules from alginate/chitosan hydrogel coatings. Biointerphases 3(4) 105-116... 

Sodium alginate Calcium cUaide Chitosan, poly-r-lysine DNA [139,140]... 

Huguet, M.L. Neufeld, R. J. Dellacherie, E. Calcium-alginate beads coated with polycationic polymers Comparison of chitosan and DEAE-dextran. Process Biochem. 1996, 31 (4), 347-353. 

Calcium-alginate and calcium-yam-alginate, methylated N-ii-NJ / dimethylaminocinnamyl) chitosan (TM65CM CS) was used to coat microparticles Wheat germ agghitiiiin (WGA)-aiichored salmeterolxinafoatefSalX)-loaded nanoparticles-in-microparticles system (NiMS)... 

Hari, P.R., Chandy, T., Sharma, C.P. Chitosan/calcium alginate beads for oral delivery of insulin. J. Appl. Polymer Sci., 59, 1795,1996. 

L. Zhao, M. Tang, M.D. Weir, M.S. Detamore, H.H. Xu, Osteogenic media and rhBMP-2-induced differentiation of umbilical cord mesenchymal stem cells encapsulated in alginate microbeads and integrated in an injectable calcium phosphate-chitosan fibrous scaffold. Tissue Eng. A 17 (7-8) (2010) 969-979. 

---