Although the incorporation of antimicrobials into wound-care products is helping to address infection concerns, the use of such agents as chlorhexidine gluconate (CHG) has presented new challenges to end-users and industry alike. Products that incorporate CHG currently lack transparency, for example, which can interfere with clinicians' ability to quickly identify signs of potential infection. Manufacturers, on the other hand, have struggled with incorporating CHG within a solvent acrylic adhesive. Addressing these limitations, Avery Dennison Medical Solutions has developed a transparent CHG adhesive delivery system (ADS) that offers antimicrobial functionality while promoting ease of use.

Current products equipped with CHG protection, such as dressings with a CHG-impregnated hydrogel island and an opaque CHG-impregnated foam disk that is covered with a transparent film dressing, may not adequately meet the needs of end-users, notes Emily Berlin, Avery Dennison Medical Solutions global market segment manager. In vascular-access applications, in particular, nurses prefer to have a clear view of the insertion site to monitor it for redness, inflammation, or blood, which may indicate an infection or other potential problems. "Neither product permits easy visibility and must be removed to check the insertion site, requiring the application of a new dressing," Berlin states.

Taking these unmet needs into consideration, the company sought to optimize its CHG ADS for use in the clinical environment. Suited for use in vascular-access or postoperative-care applications, the technology can be offered in a transparent film dressing, which provides clinicians with a clear view of the insertion or incision site. The adhesive system is capable of absorbing moisture and exudates as well.

In addition to its transparency and ease of use, ADS has demonstrated efficacy against a range of bacteria and yeast. The company reports that the system exhibited a cytotoxicity profile of Grade 0 during testing, compared with two commercial products that each had a Grade 3 cytotoxicity profile. Furthermore, these data indicate that the company was able to successfully incorporate CHG into a solvent acrylic adhesive formulation, which has been historically difficult, according to Berlin.

"We had to do some creative development work," she says. "The CHG molecule is chemically incompatible with the adhesive--one hydrophobic, one hydrophilic--so the challenge [was] in how to get the CHG molecule effectively incorporated." Because of this chemical incompatibility, companies typically opt to impregnate the CHG molecule into a different matrix rather than incorporate it into the adhesive formulation.

Having successfully incorporated the antimicrobial into the adhesive, Avery Dennison Medical Solutions is using the technology developed for the CHG formulation to further explore other combinations of adhesives and antimicrobials that haven't previously been possible. The CHG transparent film dressing is currently pending FDA clearance.

Avery Dennison Medical Solutions
Chicago