Biologically inert water-insoluble

This subject can be considered in terms of five different types of molecules or materials (a) biologically inert, water-insoluble polymers (b) water-insoluble polymers that bear biologically active surface groups (c) water-swellable polymeric gels, or amphiphilic polymers that function as membranes (d) water-insoluble but bioerodable polymers that erode in aqueous media with concurrent release of a linked or entrapped bioactive molecule and (e) water-soluble polymers that bear bioactive agents as side groups. 

Solubility/miscibility Insoluble in ethanol. Soluble to twice its weight (2 x grams) in water (xml). Soluble in glycerol and propylene glycol Biological considerations Virtually biologically inert Chemical compatibility/Stability considerations None Uses (routes) Orally, as diluent or viscosity increaser in solvents... 

Although pigments, because they are practically insoluble in water and — if at all — only sparingly soluble in common solvents, are largely biologically inert, it is the responsibility of the pigment manufacturer and producer to comply with legal requirements. 

Enzymes are immobilized by attachment to or confinement in water-insoluble materials (Fig. 1). Enzymes can be immobilized by adsorption on biologically inert carriers like organic polymers, glass, mineral salts, metal oxides, and different silicates. Since enzymes retain their activity for a longer time in an undissolved form, many reactions catalyzed by enzymes can be carried out in continuous systems. Immobilized enzymes can be used in agitated vessels, fluidized or Fixed bed tower reactors40). 

Zirconium is generally nontoxic as an element or in compounds (97,98). At pH normally associated with biological activity, zirconium chiefly exists as the dioxide which is insoluble in water and in this form zirconium is physiologically inert. 

Solubility /miscibility Practically insoluble in water, glycerol, or ethanol Biological considerations Practically inert... 

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