Preparation of Calcium Alginate

Calcium alginate is a cream-colored substance that is gelatinous in form. The solution is a water-insoluble gel that, according to "Immobilization of Enzyme and Cells" by Gordon F. Bickerstaff, has been in use since 1944 in the food and drug industry to thicken, emulsify, form and gel various products. Due to its properties, it is a common gel used in immobilizing enzymes and cells for research and application purposes.

Preparing Calcium Alginate

• Alginic acid is extracted from sea weed. The acid dissolves into sodium alginate when the seaweed is broken down and stirred into a hot solution. After this, the hot solution must go through a difficult filtering process to obtain sodium alginate that actually can be used to create calcium alginate. Dilution of the hot solution is followed by filtering through a filter cloth and introduced to forced air which helps separate the solution from the residue. The actual sodium calcium alginate dissolves in water, while other minerals that have accumulated in the solution do not. The sodium alginate is then finally extracted from the water-like solution after the other minerals have been removed.

  As noted in "Cell Adhesion" by Martin Hjorsto and Joseph Roos, the sodium alginate solution can then be dropped into a calcium salt solution which creates a gel substance known as calcium alginate.

Medical Dressings

• Apart from its use in food and pharmaceutical industries, calcium alginate is used in the medical industry as one of the key substances in dressings. Calcium alginate dressings are used primarily in wounds that experience a moderate amount of fluid drainage such as pressure ulcers, diabetic ulcers, graft sites, trauma wounds as well as first and second degree burns. According to "Wound Care Essentials" by Sharon Baranoski and Elizabeth Ayello, when alginate dressings come in contact with wound drainage, a gel is formed that helps maintain a therapeutic environment for the wound.

  The calcium alginate gen can absorb up to 20 times its own weight, reducing the accumulation of drainage fluid on the actual wound site. These dressings are usually found in sheet and pad forms that can readily be purchased and applied onto the wound. Usually, calcium alginate dressings are replaced once every day, depending on the amount of drainage. They should never be used by themselves, as they required a secondary dressing to help contain the wound area and may not be most suitable for application on extremely fragile skin.