Medical Device Link.

SPECIAL REPORT

Supplier of hydrogel products First Water makes its absorbent gel therapy system available to manufacturers of wound-care products through collaborative ventures.

Wound-care technology represents a diverse range of products. They run the gamut from humble bandages that simply cover a wound to next-generation active products that deliver bioactive compounds to the wound site and may even involve tissue engineering. Somewhere in the middle are so-called advanced products that heal wounds by promoting a moist environment.

While active wound-care products have the potential to heal wounds that could not be healed before and generate tremendous market growth in the process (see “The Future of Wound Care” by Stuart Jackson and Jeffrey Stevens in the January/February 2006 issue of sister magazine MX at www.devicelink.com/mx), more-conventional products will not be going away any time soon. Not surprisingly, that is where many suppliers of products and services to manufacturers of wound-care products are channeling their R&D efforts.

Just-in-Time Technology

Advanced wound care is a rather relative term, says Colleen Ward, business director, medical, at Avery Dennison Medical (Turnhout, Belgium). “Something that was advanced at one time may be fairly conventional now. Look at hydrocolloids and foams: they have been around for 30 years, but people still put them in the advanced bracket,” she notes. As for active wound-care technology, that has its own set of caveats, suggests Ward.

“Avery is closely watching developments in active care technology and doing some work in this field, but you have to be careful not to get too far ahead of the curve,” explains Ward. “Look at what happened to Dermagraft, a fantastic product that was shut down because it was too advanced . . . and too costly for the market.” (New York City– based Advanced Biohealing Inc., which bought the manufacturing and marketing rights to the dermal substitute from Smith & Nephew, plans to relaunch the product in 2007.)

That is not to say that Avery Dennison places less emphasis on R&D. Au contraire: the firm is pursuing research into the use of diagnostic sensors and radio-frequency identification in wound dressings. Combining these two functionalities into wound dressings is likely to be the next stage in the technology’s development, according to Ward. Research conducted by Avery Dennison into potential applications for intelligent dressings shows considerable interest among specialists in a number of areas. The opportunity exists not just for treatment, stresses Ward, but also for the prevention of certain types of wounds such as decubitus ulcers. “The technologies exist,” she says. “The question is whether they can be combined into a cost-effective solution that delivers measurable results for both the patient and hospital.”

One next-generation product that is already working miracles, according to Ward, is V.A.C.- brand Negative Pressure Wound Therapy (NPWT) from Kinetic Concepts Inc. (San Antonio, TX, USA). Avery Dennison manufactures the adhesive drape that is used with the device.

V.A.C.-brand NPWT uses controlled negative pressure to promote wound healing and to remove infectious materials and other fluids from the wound site. The computer-controlled therapy unit comes with a canister, sterile plastic tubing, foam dressing, and clear drape dressing. The foam dressing is placed into the wound. The wound area is then sealed with a filmic adhesive drape that resembles a large bandage. One end of the tube is connected to the foam using a connector; the other end is attached to a canister that is hooked up to the control unit. Infectious materials and other fluids are sucked from the wound through the tube and collected inside the canister.

“This system produces phenomenal results,” says Ward. “Wounds that tend to remain open [when treated using conventional methods], closed very rapidly, restoring the patient’s quality of life.”

Accelerating the healing process is an important function of wound dressings, but it’s not always the only role it plays. Ward points to her firm’s recent development of odour-absorbing hydrocolloid dressings as another example of innovation that works.

Charcoal-based wound dressings are traditionally used to manage odours, but they have some drawbacks, according to Avery Dennison. The presence of wound serum deactivates the charcoal, thereby inhibiting the adsorption of odour molecules. The dressings also require adjunct fixation to hold them in place.

As an alternative, Avery Dennison developed hydrocolloid adhesives based on cyclodextrins that are suitable for direct wound contact. In vitro trials have proven the material’s odour absorption properties when serum is present. The dressings also are able to absorb a significant amount of fluid and are self-adhesive.

Wound-care dressings using this technology are being introduced into the market by Medline Industries (Mundelein, IL, USA) under the brand name Exuderm Odorshield.

The Virtues of Transparency

InteliCoat (Wrexham, UK), a supplier of flexible components to wound-care, ostomy, and medical device OEMs, recently introduced polyurethane (PU) films on a transparent matte backing. This makes the film almost invisible when it is applied to the skin.

“Thin PU films lack rigidity,” says Fraser Kinnaird, medical market manager. “They normally require a backing material in order for them to be applied to the patient. If these conformable materials are unsupported, they are difficult to apply to the skin and tend to wrinkle up.”

A number of products are currently available with paper backing layers. But it’s difficult to put the dressing directly over a wound site if you can’t see through it, explains Kinnaird. “The advantage of transparent casting liners is that you can see exactly where you are applying the dressing.”

There are other PU films with transparent backings, as well, concedes Kinnaird, but the InteliCoat material’s matte surface sets it apart from the competition. Glossy surfaces tend to draw attention to the dressing. “The more discreet the dressing, the greater its acceptability,” says Kinnaird. The matte surface also provides a benefit when the product is used to make incise drapes for the surgical suite, where it minimizes the amount of reflected light.

Self-Supporting Systems

InteliCoat tends to focus on advanced wound-care applications, says Kinnaird, and one project that is getting quite a bit of attention at the company is the development of self-supporting systems. “We are working on a material that has all of the characteristics of a thin PU film—breathability, low coefficient of friction, and so forth—with enough built-in rigidity to forego application films or paper,” he explains.

The firm is also actively investigating the antimicrobial properties of silver for its products. This is not necessarily novel research in the grand scheme of things, admits Kinnaird, but InteliCoat can offer something that is beyond the scope of many other companies: the ability to create products that exactly match the needs of its customers.

For manufacturers sourcing wound-care products, the holy grail continues to be an adhesive that “sticks for seven days and then peels off without any trauma,” says Kinnaird. That will have to be a topic for another day, but there is no denying that tremendous progress has been made in optimizing adhesives for wound-care applications. Stickiness is but one part of the equation for adhesives companies, which are being asked to provide a great deal more functionality.

“We are bringing together various technologies at Adhesives Research (Limerick, Ireland) to increase the functionality of our adhesives,” says Mary Robertson, business manager at the company’s ARcare medical division. “They do their part of sticking, but they are also engineered to clear up wound sites. Porous adhesives are a good example,” she adds.

Porous adhesives allow moisture to pass through the adhesive layer. “The amount of porosity can be controlled,” says Robertson, “and the adhesives can be loaded with drugs. So the exudate migrates away while the pharmaceutical agent treats the wound,” she explains.

Taking it a step further, Robertson envisions rolls of film with drug-embedded adhesives that dissolve once they have performed their job. The company has gained considerable expertise in erodable adhesives in the development of transdermal patches, which it has applied to this project.

We can quibble about the precise meaning of advanced wound-care, but it’s clear that the companies cited in this article are serious about advancing the technology. More firms can be found in the accompanying Resources sidebar, which includes capsule company and product descriptions.