This article aims to give an insight into a few of the most significant advancements in the last six years and offer guidance on which technologies could be most suitable for pharmacies.

If we look back only a few years to the turn of the millennium, first aid plasters and dressings were generally restricted regarding material (fabric or plastic), shape, size and finish (clear, flesh-coloured, blue for non-domestic use, or those for children featuring cartoon characters or animals). Purchase of anything else usually followed a pharmacist’s recommendation of a specific dressing, frequently accompanied by adhesive tape to keep it in place. However, more recently the first aid mass market is seeing an influx of advanced wound healing technologies from the medical industry. New technologies include plasters and dressings containing polyurethane (PUR) gel or metallic silver, and the more simple innovations like plaster application methods (i.e. liquid adhesive and spray plaster).

Moist wound healing

In 1962 Dr George D Winter demonstrated that wounds should be kept moist to promote healing, contrary to conventional wisdom that wounds should be allowed to dry and form scabs. In an experimental model, Dr Winter found that tissue regrowth occurred more than twice as quickly in a moist environment as under a scab.[1]

Figure 1. The effect of moist wound healing. Ref: BDF AG

Today, the principle of moist wound healing is accepted in the professional sector but, until 2002, this technology was not available in the mass market. Moist wound healing creates and maintains optimal moist conditions, which help cells to grow, divide and migrate at an increased rate during the formation of new tissue. It also enables the formation of an aqueous medium (wound exudate) containing nutrients and vitamins essential for cell metabolism and growth. This wound exudate provides the ideal environment for immune system cells to destroy invading pathogens, foreign bodies and dead tissue. By preventing the formation of scabs, moist wound therapy allows epithelial cells to spread horizontally outwards through the wound exudate and rapidly close the wound. The likelihood of scarring is reduced, which in turn offers better cosmetic results.

Benefits of pur technology

Plasters and dressings containing PUR gel technology have been available on the mass market since 2002 for the treatment of minor wounds and first or second degree burns. This technology differs from conventional hydrocolloids in that the wound pads are made of a PUR foam matrix, embedded with super-absorbent particles and covered with a thin polyurethane film. Unlike conventional hydrocolloids, PUR gel dressings:

• Are stable in contact with wound exudates, even after days of application;
• Do not leave a slimy gel that has to be removed or rinsed out of the wound;
• Are permeable to water vapour and oxygen, preventing maceration of the surrounding skin.

PUR gel technology not only helps to create a moist wound healing environment, it also selectively absorbs water from the wound, leaving essential nutrients for optimal healing. The technology provides an effective barrier to external influences and contamination by bacteria, and reduces the risk of infection by maintaining an efficient local defence mechanism in the wound.[2]

With a first degree burn, the general characteristics are redness and pain, while in second degree burns there may be swelling and blisters. The foam contained in PUR burn products adjusts to the contours of individual burns and acts as a protective cover. This cover helps the affected area to heal undisturbed, resulting in pain reduction and less risk of infection if blisters have burst.

Figure 2. Appearance of moist healing wounds. Ref: BDF AG

Silver wound healing

Silver has been known to mankind for over three centuries and has made more contribution to human health and medicine than any other metal. The introduction of sustained silver-release dressings in the last 20 years marks a rebirth of silver in wound therapy. Improved technology has enabled manufacturers to deliver silver ions to wounds and provide safer and more efficacious antibacterial therapies with barriers against re-infection.[3]

Sustained silver-release dressings are now well established in the management of acute and chronic wounds and burns. Silver as silver nitrate, colloidal silver or silver sulphadiazine cream has been a choice antiseptic for wound care for many generations and numerous clinical studies have substantiated its merits in treating venereal infections, warts, chronic ulcers and surgical incisions.[4]

Since 2005, plasters and dressings containing metallic silver have been available in the mass market. These come in a variety of sizes to treat wound types ranging from superficial lacerations to deeper wounds, all of which could be prone to infection.

Figure 3. Silver technology - mode of antiseptic action

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As soon as the metallic silver, contained in the polyethylene net in the wound pads, comes into contact with wound exudate or blood, silver ions are immediately released. The bacteria absorb the liberated silver ions, which ultimately inactivate bacterial DNA and RNA, thus inhibiting replication. The ability of silver to kill or otherwise inhibit a wide range of Gram-positive and Gram-negative bacteria is unequivocal.[5]

While most bacteria are able to develop resistance to anti-microbial agents, very few micro-organisms become resistant to silver, confirming the power of silver technology as a treatment against a wide range of bacteria. Antiseptics may be effective only for a short time after application, and any bacteria not destroyed will replicate every 20 minutes. Silver contained in wound dressings will continually release ions into the wound, providing a long-lasting effect.

Spray appplication

2006 saw the introduction of spray plaster technologies into the first aid market. These latest innovations are based on advanced liquid wound care techniques traditionally used for surgical wounds. In sprays, however, the liquid formulae are applied to affected areas via an aerosol. Various formulae are available in the mass market. One contains a solvent co-polymer mixture; on application the solvent evaporates, leaving polymer components on the skin to form a protective film.

The film is inert, breathable, transparent and waterproof and could make obsolete the use of large protective dressings for minor cuts and grazes on awkward areas. This technology is only suitable for superficial cuts and grazes, but its durability makes it an ideal solution for protection from dirt and other external influences.

Table 1. First aid technology reference guide

References

1. Winter GD. Formation of the scab and the rate of epithelization of superficial wounds. Nature 1962; 193: 293–294.

2. Herman MHE, Hutchinson JJ. Treatment of wound with occlusive dressing: clinical and bacteriological aspects. Akt Dermatol 1991; 17: 91–94.

3. Morgan DA. Wound management products in the Drug Tariff. Pharm J 1999; 263: 820–825.

4.Lansdown ABG. The role of silver. The European Tissue Repair Society Bulletin 2002; 9(4) (www.etrs.org/bulletin9_4/section7.html ).

5. Lansdown ABG. A Review of the use of silver in wound care: facts and fallacies. Brit J Nursing 2004; 13(6) Suppl: S6–S19.