Sodium Alginate

Synonyms: Alginato sodico; algin; alginic acid, sodium salt; E401; Kelcosol; Keltone; natrii alginas; Protanal; sodium polymannuronate.

Description: Sodium alginate occurs as an odorless and tasteless, white to pale yellowish-brown colored powder.

Chemical Name: Sodium alginate

Stabilizing agent; suspending agent; tablet and capsule disintegrant; tablet binder; viscosity increasing agent.

• Sodium alginate is used in a variety of oral and topical pharmaceutical formulations.

• In tablet formulations, sodium alginate may be used as both a binder and disintegrant it has been used as a diluent in capsule formulations.

• Sodium alginate has also been used in the preparation of sustained-release oral formulations since it can delay the dissolution of a drug from tablets, capsules, and aqueous suspensions.

• The effects of particle size, viscosity and chemical composition of sodium alginate on drug release from matrix tablets have been described.

• In topical formulations, sodium alginate is widely used as a thickening and suspending agent in a variety of pastes, creams, and gels, and as a stabilizing agent for oil-in-water emulsions.

• Recently, sodium alginate has been used for the aqueous microencapsulation of drugs, in contrast with the more conventional microencapsulation techniques which use organicsolvent systems.

• It has also been used in the formation of nanoparticles.

• The adhesiveness of hydrogels prepared from sodium alginate has been investigated, and drug release from oral mucosal adhesive tablets, buccal gels and vaginal tablets based on sodium alginate have been reported.

• The esophageal bioadhesion of sodium alginate suspensions may provide a barrier against gastric reflux or site-specific delivery of therapeutic agents.

• Other novel delivery systems containing sodium alginate include ophthalmic solutions that form a gel in situ when administered to the eye an in situ forming gel containing paracetamol for oral administration nasal delivery systems based on mucoadhesive microspheres and a freeze-dried device intended for the delivery of bone-growth factors.

• Hydrogel systems containing alginates have also been investigated for delivery of proteins and peptides.

• In addition, sodium alginate microspheres have been used in the preparation of a footmouth disease DNA vaccine and in an oral vaccine for Helicobacter pylori; chitosan nanoparticles coated with sodium alginate may have applications in mucosal vaccine delivery systems.

Sodium alginate is incompatible with acridine derivatives, crystal violet, phenylmercuric acetate and nitrate, calcium salts, heavy metals, and ethanol in concentrations greater than 5%. Low concentrations of electrolytes cause an increase in viscosity but high electrolyte concentrations cause salting-out of sodium alginate; salting-out occurs if more than 4% of sodium chloride is present.

Sodium alginate is widely used in cosmetics, food products, and pharmaceutical formulations, such as tablets and topical products, including wound dressings. It is generally regarded as a nontoxic and nonirritant material, although excessive oral consumption may be harmful.

Observe normal precautions appropriate to the circumstances and quantity of material handled. Sodium alginate may be irritant to the eyes or respiratory system if inhaled as dust. Eye protection, gloves, and a dust respirator are recommended. Sodium alginate should be handled in a well-ventilated environment.

Alginic acid; calcium alginate; potassium alginate; propylene glycol alginate.