International Numbering System (INS) for Food Additives: 402
Food additives Europe numbers: E402
Functional Category
Emulsifying agent; stabilizing agent; suspending agent; thickening agent.
Applications in Pharmaceutical Formulation
Potassium alginate is widely used in foods as a stabilizer, thickener, and emulsifier; however, its use as a pharmaceutical excipient is currently limited to experimental hydrogel systems. The viscosity, adhesiveness, elasticity, stiffness, and cohesiveness of potassium alginate hydrogels have been determined and compared with values from a range of other hydrogel-forming materials.(1) The effect of calcium ions on the rheological properties of procyanidin hydrogels containing potassium alginate and intended for oral administration has also been investigated.(2)
Description
Potassium alginate occurs as a white to yellowish, fibrous or granular powder; it is almost odorless and tasteless.
Stability and Storage Conditions
In the solid state, potassium alginate is a stable material that is not prone to microbial spoilage. Over time, a slow reduction in the degree of polymerization can occur, which may be reflected in a reduction in the viscosity of solutions. As both temperature and moisture can impair the performance of potassium alginate, storage below 258C is recommended. Potassium alginate solutions are stable at pH 4–10; long-term storage outside this range can result in depolymerization of the polymer through hydrolysis. Gelation or precipitation of the alginate can occur at pH values less than 4. Liquid or semisolid alginate formulations should be preserved: suitable preservatives are sodium benzoate, potassium sorbate, or parabens. Potassium alginate should be stored under cool, dry conditions in a well-closed container.
Incompatibilities
Incompatible with strong oxidizers.
Safety
Potassium alginate is widely used in food products. It is currently used as an excipient only in experimental pharmaceutical formulations.