Battling Infection at the Material Level
Hospital-borne infection is always a concern to healthcare professionals as the result can lead to increased care costs, increased hospital stay, and even patient death. In order to help combat this critical problem, one company has focused on combating these infections at the material stage. This article focuses on their antimicrobial material and the benefits the use of it offers.
Michael F. Adams is the president and CEO of AdvanSource Biomaterials, Khristine L. Carroll is the VP of sales & marketing, and Harold Garey is a sr. polymer scientist with the company. Questions regarding this article should be submitted to email@example.com.
The recent influx of drug resistant hospital-borne infections, particularly common with indwelling catheters, has drawn widespread interest from pharmaceutical and device manufacturers alike. In addition to the added cost of treating these infections, recent healthcare initiatives are setting into effect more stringent reimbursement policies and mandating hospitals to reduce the rates of infection. These antibiotic resistant infections (ARIs) including methicillin-resistant Staphylococcus aureus (MRSA), result in high cost for treatment, extended hospital stays, and in some cases, patient mortality. Costs for treating ARIs have been reported to be $20B annually in the U.S.1
Use of polymeric materials in medical devices has been associated with an increasing incidence of patient infections. As such, advancing material science technology has become increasingly critical to ensuring antimicrobial characteristics are incorporated into the device. AdvanSource Biomaterials antimicrobial polymers have been specifically developed to help reduce the incidence and severity of infections in patients subject to indwelling medical devices.
Organic vs. Inorganic Antimicrobial Agents
Antimicrobial agents may be classified as either organic or inorganic materials. Organic antimicrobial agents tend to be volatile, especially at elevated (processing) temperatures. In addition, transfer of the antimicrobial agent to the skin via handling the finished antimicrobial products is a concern. Sweat on the hands is an excellent way to absorb the applied agent and contaminate one's skin. Also, the organic antimicrobial agents tend to be unstable and to break down at mechanical processing temperatures.
Inorganic anti-microbial agents are normally stable at processing temperatures, and are not volatile. These include metal ions (e.g., Ag+, Cu++, and Zn++. AdvanSource antimicrobial polymers contain silver ions (Ag+), which are preferred as they possess a wide spectrum of antimicrobial activity, safety, and heat stability.2
Traditional methods for incorporating antimicrobial additives in resin systems currently in use by material manufacturers are performed using prefabricated resin and are incorporated in one or a series of secondary steps that add cost, complexity, and the potential of material degradation to the manufacturing process. Typically, the antimicrobial agent is added to the finished resin by compounding or kneading the additive into the resin as a secondary processing step. This is often accomplished using melt extrusion and pelletizing equipment and requires the additive to be heat stable for extended periods. In addition, uniformity of dispersion is often difficult to achieve with this technique.
The ASB Advantage
AdvanSource Biomaterials' antimicrobial polymers utilize proprietary manufacturing techniques and processes to provide a fully homogenous material, thus ensuring uniform dispersion of the antimicrobial agent throughout the finished polymer. The company developed a family of proprietary polymers incorporating antimicrobial additives into the pre-polymerization stage. The materials are beneficial and increasingly sought after for use in indwelling catheters, ports, and other access devices.
Due to the homogeneous nature of the material, the active silver ions incorporated in the antimicrobial polymers are stabilized by their association with a carrier, such as a phosphate (particularly zirconium phosphate), water soluble silicate powder, zeolite, and ion exchange resin. Secondary additives may also be incorporated in antimicrobial polymers, such as antioxidants, echogenic, and antithrombolytic agents, color stabilizers, and radiopacifiers. The proprietary process enables ASB to achieve lot-to-lot consistency and tailor the material to the specific application requirements of its customers. Essential to the homogeneous manufacturing process is that, with the agents formulated into the chemistry of the materials, the base resin maintains the characteristics inherent to the polymer without diminishing the effect of the antimicrobial agents even after secondary processing operations.
The Global Impact
Some of the most exciting areas for convergence lie in technologies such as combining a polymer with a drug or biologic. Polymers offer a unique platform in that they can easily be impregnated with a therapeutic agent and, based on the polymer, can be released very quickly or very slowly based on the indication. With the trend toward advancing material science technology to enhance device functionality, including the ability to disperse the antimicrobial agents homogeneously throughout the final product, this technology enables device makers to be poised to increase efficiency, reduce hospital driven treatment cost, and further support patient healing in the fight against hospital-acquired infections.
1 Marler, Bill. "Antibiotic-Resistant Infections (MRSA) Cost the U.S. Healthcare System in Excess of $20 Billion Annually" www.mrsablog.com. October 19, 2009.
2Guggenbichler, et al., Infection 1999 27 Suppl. 1, S16-S23.