Multipurpose functionality has become an expectation in the modern lifestyle. A washing machine is no longer just a washing machine but rather a computerized appliance that can automatically order its own detergent when it senses supplies are low. An alarm clock isn't only a device to wake you up. It's an Internet of Things-enabled personal assistant, capable of sharing the weather forecast, streaming your favorite songs on demand, and calculating how you're measuring up against your latest fitness goals. Our phones aren't just for talking. They're mini computers, calculators, cameras, video recorders, and audio players. Social media apps aren't just for keeping up with friends. If you like something you see on Pinterest, you can click and buy it instantly.

Some vascular access dressings do more than hold an IV line in position. For instance, this adhesive dressing contains the additive chlorohexidine gluconate (CHG) and is designed to deliver antimicrobial protection while providing a secure hold. (Credit: Vancive Medical Technologies).

For the healthcare industry, ever in search of greater efficiencies, this trend toward multifaceted, ubiquitous technology is a perfect fit to help solve complex challenges and patients’ everyday problems. It may become rarer to have a medical device or drug that only performs function A or is just for dealing with symptom B. As providers, practices, hospitals, and device designers explore new care delivery models, there is a burgeoning opportunity to discover how materials, instruments, therapies, and protocols designed to serve one purpose might be reinvented or augmented to serve another.

This article focuses on the use of additives in pressure-sensitive adhesive dressings and patches relative to this trend. How can new applications help patients heal faster, more comfortably, with more mobility? Beyond attaching something to the body, what more can an adhesive material do to enable healthcare providers to try new therapies, gather meaningful patient insights, and achieve consistently better outcomes?

Additives Offer Ancillary Benefits

Additive use in adhesives is not brand new, nor is the notion of adhering monitoring equipment to the body or covering a wound with a dressing. But until recently, each of these activities has been rather singular in focus. For example, nicotine patches have served primarily one purpose: delivering a drug to help with smoking cessation. The adhesive patch has acted only as a drug-delivery vehicle.

This diagram illustrates how additives such as chlorohexidine gluconate (CHG) can be incorporated into an adhesive dressing to provide antimicrobial protection. (Credit: Vancive Medical Technologies)

Now it's time to ask: What else can an adhesive medical device do for the practitioner, patient, healthcare institution, or retail healthcare product consumer? How can an additive enable the adhesive to serve multiple purposes and deliver greater value?

Another way to look at this opportunity is to think of it as getting two-in-one or three-in-one capabilities. Or you can consider this analogy to the Oscars: An adhesive medical product can have a primary purpose (lead actor) and secondary purpose (best-supporting actor). When both deliver a stellar performance, the rewards come rolling in.

Here are some examples of how additives can be incorporated into pressure-sensitive adhesives for multiple end uses, listed according to both primary and ancillary functionality. Some applications exist today; others may be in development or may be hypothetical.

Product: Catheter insertion site or postoperative site dressing.

Primary function: Stabilize and cover an intravenous catheter site or cover and protect a surgical site wound postoperatively.

Additive: Ionic silver, chlorhexidine gluconate (CHG), or other antimicrobial agents.

Secondary functions:*

  • Antimicrobial protection.
  • Moisture management to encourage wound healing.
  • Transparency for easier wound monitoring and reduced dressing changes.

*Characteristics offered in a proprietary adhesive formulation used in some IV site and postoperative dressings containing CHG, an antiseptic agent with broad antimicrobial and antifungal activity. All three functions may not be available in other dressings.

Product: Chronic wound dressing.

Primary function: Protect wound and absorb exudate.

Additive: Glycerin, vitamins or moisturizing agents, analgesic.

Secondary functions:

  • Moisturization.
  • Skin regeneration.
  • Pain relief.

Product: Ostomy flange adhesive.

Primary function: Secure ostomy flange to stoma.

Additive: Glycerin, vitamins or moisturizing agents, cyclodextrin (odor absorber).

Secondary functions:

  • Irritation prevention.
  • Stoma site healing.
  • Odor control.

Product: Facial blemish patches.

Primary function: Conceal cold sores, acne, scars, discoloration, or other blemishes.

Additive: Healing agent, analgesic, ultraviolet (UV) sun ray blocking agent.

Secondary functions:

  • Pain relief.
  • Inflammation reduction.
  • Healing properties.
  • UV protection.

Far-Ranging Formulation Possibilities

Virtually any adhesive can be impregnated with various additives, whether the adhesive hails from a family of rubbers, silicones, acrylates, or other substances. That said, materials science expertise is required to find the right formulation. One of the greatest challenges is identifying a solution that is both effective and stable over time and under different conditions. For example, some additives can degrade during high-temperature processing.

The science of adhesive additives requires materials experts to evaluate different possibilities at the molecular level. For instance, chemists must address the inherently hydrophilic or hydrophobic characteristics of the primary base material. It can be very difficult to incorporate a water-soluble additive into an adhesive that is hydrophobic. But it's not impossible.

Adhesive materials with additives can be created in a variety of form factors. Additives can go into opaque, absorbent hydrocolloids as well as super-thin, transparent acrylic adhesive films, and everything in between. The end-use application will help determine the best base material. Some questions to consider:

  • Does the adhesive need to conform to a difficult-to-fit spot (i.e., foot, elbow, facial crevice)?
  • Can the adhesive/additive combination adhere and perform effectively regardless of high moisture levels (i.e., use on or around the mouth, wear time in the pool or shower, etc.)?
  • How long is the desired wear time and expected activity level (daily, overnight, multiple days, a week or more)?
  • What are the material's upper and lower temperature limits for processing and storage?
  • Can the adhesive/additive solution tolerate sunlight in storage and/or patient use?
  • How will the adhesive/additive respond to changes in patient temperature and perspiration?
  • Does the product need to be transparent for cosmetic or clinical reasons? Does it need to match different skin tones?

OEM Quality System and Regulatory Considerations

Adhesive medical products with additives can have very diverse applications. It's important to carefully consider the intended use and any claims the OEM may wish to make regarding the end product. The regulatory lines between devices, drugs, and cosmetics can be blurry. For example, in defining cosmetics and drugs according to their intended uses, the Federal Food, Drug and Cosmetic Act says:

  • Cosmetics are “articles intended to be rubbed, poured, sprinkled, or sprayed on, introduced into, or otherwise applied to the human body … for cleansing, beautifying, promoting attractiveness, or altering the appearance.”
  • Drugs are “articles intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease” and “articles (other than food) intended to affect the structure or any function of the body of man or other animals.” (Source: FDA)

Similarly, there can be a fine line between the definitions and classifications of medical devices and drugs. For instance, a basic elastic bandage is considered a Class 1 medical device. But when that dressing is enhanced to deliver protection, treat a disease, or monitor a condition, its classification changes, becoming subject to greater regulatory review and scrutiny.

The FDA oversees both nonprescription over-the-counter (OTC) drugs and prescription drugs. Additives such as UV blockers, vitamins, moisturizing agents, essential oils, and some pain relievers may be considered OTC ingredients. If the product contains only FDA-approved OTC ingredients, and the formulation and labeling conform to the FDA OTC Drug Monograph, then the product does not need to go through the new drug approval process. The FDA describes monographs as being like familiar recipes that are well tested for safety and efficacy. If an additive or formulation does not conform to a standard recipe, it's likely the OEM will need to pursue the more rigorous new drug approval process, including animal and human studies. OEM operations and possibly suppliers’ factories, too, may need to meet pharmaceutical industry quality standards.

It's crucial to have a solid regulatory strategy in place. The road to developing adhesives with additives also will be smoother if material development partners have prior experience working in the functional area of interest, such as wearables, chronic disease management, rehabilitation, cardiovascular applications, or wound care.

In conclusion, when healthcare providers and device developers can deliver a treatment or service that is effective, convenient, and cost-effective, it's a win-win for patients and all industry players. Additive use in medical adhesive products opens new possibilities for collaborative innovation in patient-centered care.

This article was written by Neal Carty, PhD, Director of R&D and Medical and Scientific Affairs for Vancive Medical Technologies, Mentor, OH. For more information, Click Here .


Medical Design Briefs Magazine

This article first appeared in the April, 2017 issue of Medical Design Briefs Magazine.

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