A composition which is particularly useful in semi-rigid medical supporting bandages comprises of 10 to 35% zinc oxide, 2 to 15% cellulose ether, 10 to 35% glycerin and 30 to 75% water. 160 g/m ² of the above composition is applied, in a conventional coating plant equipped to process highly viscous materials, to a gauze bandage 10 cm wide and having 20 threads. The substrate has a selvedge on both sides and the resultant coated product is wound on a polystyrene core having 10 mm inside diameter and 14 mm outside diameter, wrapped in wax paper, and wrapped in polyethylene coated aluminum foil which is then fused.

Bandages of the foregoing description have been used for many years in the treatment of leg injuries or disorders. They are used for many years in the treatment of thrombosis, for the healing of leg ulcers, as a supporting dressing in minor injuries, to prevent swelling of broken limbs after removal of the plaster cast, and as semi-rigid compression dressings in cases of varicosis, ulcers, phlebitis, and leg edema.

One of the most significant ideas to change the nature of wound dressing materials has been the concept of moist wound healing. Moist wound healing refers to the provision and maintenance of optimal hydration of the exposed tissues in the wound, that is, wound tissues should be physiologically moist, not dry but not wet. Moist wound healing dressings usually fall into 1 of these 3 performance categories with regard to their effects on tissue moisture levels - dressings that absorb excessive wound exudate, dressings that maintain existing levels of tissue moisture, and those that add moisture to the tissues. (Liza G Ovington, Advances in wound dressings, Clinics in Dermatology 2007: 25, 33-38).

Dressings that absorb excessive wound exudates have a high capacity for capturing and holding fluid. In such dressings generally calcium alginate (fibres or powder) and foams are used as spatiality chemicals. While various types of hydrocolloids and transparent films are used in dressings that maintain hydration of tissues. Hydrocolloids are gel forming polymers and adhesives held in fine suspension on the backing of film or foam.

Lastly the dressings that provide moisture to the wound are hydrogels of various polymers such as : glycerin polyacrylate polymer is a chemical available under the tradename Hispagel. The glycerin polyacrylate has excellent water solubility, moisture retention and lubrication properties. Additionally this polymer also has the non drying property due to strong bonding of water with the polymer molecule. The glycerin polyacrylate will work on skin to form a film protecting the wound from outside particles and in combination with glycerin maintain a high hydration level (US Patent 5902600). Hydrogels consist essentially of 20-97% of an aqueous liquid and a cross-linked hydrophilic polymer. A variety of hydrophilic polymers have been used for the production of hydrogels viz CMC, alginates, HEMA, chitosan, pectin, petroleum jelly etc.

Recently some advanced wound dressings have been developed that interact with the biochemical environment in wound and promote healing. Such dressings are generally composed of a homogeneous mixture of 55% bovine collagen and 45% oxidised regenerated cellulose. When placed in the wound these collagen-based dressing chemically binds to enzymes and renders them inactive, bringing their active levels back down into the ranges found in healing wounds, which may then allow healing to progress.

The latest addition to the wound dressings are commonly classified as 'Antimicrobial Dressings'. An antimicrobial agent such as iodine, ionic silver, silver + charcoal and polyhexamethyl biguanide (PHMB) are incorporated into foams, hydrocolloids, alginates, and fibres. Most popular among these are the silver containing dressings where these products release silver cations into the wound as they absorb or come in contact with wound exudate.

A cursory look at the wound dressings indicates that a large number of specialty chemicals and finishes are required in their production and these may include, polyurethane, silicones, zinc oxide, glycerin, gelatin, alginates, gum arabic, agar agar, calcium alginate, hydrogels of CMC, alginates, HEMA, chitosan, pectin, petroleum jelly, glycerin polyacrylate, collagen, iodine, ionic silver, charcoal and polyhexamethyl biguanide (PHMB) etc. Coating is a preferred method of application.