Gastrointestinal tract, stability under conditions

The stability of the divalent state of zinc is such that it acts neither as an oxidizing nor as a reducing agent under the physiological conditions of the mammalian gastrointestinal tract. 

To understand the behavior ofglucoside conjugates and specific bound residues under conditions found in the gastrointestinal tract (G IT) of humans and livestock species. The term behavior implicitly includes stability and propensity to be systemically absorbed. 

Chitosan is acid-soluble because its crystal structure can be broken down under acidic conditions. To preserve the stability of chitosan gel under gastrointestinal tract delivery or enzymatic degradation, the amine groups on its polymeric chains must be fixed by chemical reagents. The ionic interactions between the positively charged amino groups on chitosan and either small anionic molecules, such as sulfates, citrates, and phosphates, or some metal ions, have been successfully used in the preparation of chitosan beads or hydrogels [94, 95]. 

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