Hydrogels complexing

Kojima Y., Isobe T., Senna M. Mechanisms of Al and titania hydrogel complex formation via a mechanical route. J. Mater. Res. 1996 11 1305-9. 

Polyionic hydrogel ( complex coacervate or polyion complex hydrogel) by mixing polyelectrolytes with opposite charge, for example, alginic acid and polylysine... 

Complex coacervate gels can be formed by mixing a polyanion solution with a polycation solution (Priftis and Tirrell, 2012). The fundamental principle (Fig. 10.11) is that polymers with opposite charged stick together and form soluble or insoluble complexes depending on the concentration and pH of the respective solutions. For example, proteins below their isoelectric point are positively charged and likely to associate with anionic hydrocolloids and form polyion complex hydrogels (complex coacervate). 

The supramolecular polymerization of 12 occurred with the aid of CB[8] to form stable, deep-purple hydrogels. Complexation of methylviologen within the hollow cavity inhibited supramolecular polymerization. Consequently, the supramolecular gel collapsed. Accordingly, the supramolecular polymer networks were crucial for gelation. 

Chung, Y.-I., et al., 2007. Enhanced bone regeneration with BMP-2 loaded functional nanoparticle-hydrogel complex. Journal of Controlled Release Official Journal of the Controlled Release Society 121 (1-2), 91-99. Available at http //www.ncbi.nlm.nih.gov/ pubmed/17604871 (accessed 19.12.14.). 

Keywords Biocompatible hydrogels Complex architectures Functionalized vinyl monomers lanus-type dendrimers Modular nature Passerini three-component reaction PEGylation of proteins Photo-responsive polymers Sequence-defined structures Tailor-made materials Ugi four-component reaction... 

The formation of microspheres from various pectin hydrogel complexes and corn zein in the presence of calcium and zinc ions has been proposed (Mukhidinov et al., 2011). It is shown that the formation of microspheres and their loading capacity for a drug (piroxicam) depend on the type of biopolymers, their ratio, the sizes of the bivalent ions, and the molecular mass of the pectin. It was supposed that complexes of pectin with zein would suppress pectin swelling in the stomach and, thereby, limit drug degradation in the GI tract. 

As a polycation, chitosan spontaneously forms macromolecular complexes upon reaction with anionic polyelectrolytes. These complexes are generally water-insoluble and form hydrogels [90,91]. A variety of polyelectrolytes can be obtained by changing the chemical structure of component polymers, such as molecular weight, flexibility, fimctional group structure, charge density, hydrophilicity and hydrophobicity, stereoregularity, and compatibility, as... 

A hydrogel with high sensitivity was prepared with chitosan (DA = 0.18) and dextran sulfate the maximum volume of the complex gel was observed in a dilute NaOH solution at pH 10.5, and was about 300 times as large as the volume at pH values below 9 [106,107]. 

Topical Formulations. Topical formulations by their very nature are usually multicomponent, and it is not surprising that neural networks have been applied to deal with this complexity. The first work was performed on hydrogel formulations containing anti-inflammatory drugs in Japan in 1997 [57], followed up by further studies in 1999 [58] and in 2001 [59]. Lipophilic semisolid emulsion systems have been studied in Slovenia [60, 61] and transdermal delivery formulations of melatonin in Florida [62]. In all cases, the superiority of neural networks over conventional statistics has been reported. 

We have noted earlier that aluminium is unusual in forming alumino-phosphate complexes in phosphoric acid solution which may be of a polymeric nature. Bearing in mind the analogies between aluminium phosphate and silica structures, it may well be that during cement formation an aluminium phosphate hydrogel is formed. Its character may be analogous to that of silica gel, where a structure is built up by the... 

Gong, J. P. (2006) Friction and lubrication of hydrogels—its richness and complexity. Soft Matter, 2, 544-552. 

Kenausis G, Taylor C, Katakis I, Heller A. 1996. Wiring of glucose oxidase and lactate oxidase within a hydrogel made with poly(vinyl pyridine) complexed with [Os(4,4 -dimethoxy-2,2 -bipyridine)2Cl]. J Chem Soc Faraday Trans 92 4131-4136. 

Bell, C, L and Peppas, N. A. Biomedical Membranes from Hydrogels and Interpolymer Complexes, VoL 122, pp. 125-176. 

The complexity of the swelling kinetics of hydrogels means that only the simplest cases can be modeled quantitatively. Thus this section focuses on identification of rate-influencing phenomena and data analysis rather than the extensive theoretical modeling of the kinetic phenomena that has been done on this subject. Reviews of theoretical modeling include those by Peppas and Korsmeyer [119], Frisch [120], and Windle [121],... 

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