The definition of a disposable device can vary. At one end of the spectrum are completely disposable, single-use devices that are designed for use on one patient during a single procedure. These items are packaged sterile by the manufacturer, and remain sterile until the package is opened. This category of disposable medical devices is not intended to be reprocessed and reused on another patient. The other type of disposable refers to a disposable component of a reusable, multi-use medical device. Polycarbonates play a pivotal role in both types of disposable medical devices. In fact, disposables utilizing polycarbonates are used in everything from drug-delivery devices and intravenous access components to renal therapy devices and surgical instruments.

Makrolon polycarbonate forms the handles of Caltorque Medical Products’ TorqueSafe instruments.

The Freedonia Group reports the U.S. medical disposables market was worth $40.3 billion in 2016, a figure that is expected to grow 4.1 percent annually to $49.3 billion in 2018. Drug-delivery and related products is the largest and fastest-growing segment of disposable medical supplies. According to the Freedonia Group, an aging population, incidence of medical conditions, and extension of insurance coverage are major growth factors. The U.S. Census Bureau reported over 46.2 million Americans 65 and older in 2014. That number is expected to grow to 56.4 million in 2020 and continue to rise to 98.1 million to 2060. There are several factors contributing to the growth in disposables, including opportunities for reduced costs and enhanced safety.

Lower Costs and Reduce HAIs

Disposable stopcocks formed from Makrolon R×1805 polycarbonate offer a convenient option for hospitals and surgical centers.

The use of disposable medical devices lowers costs, increases efficiency, and reduces the spread of infection. Reusable, multiple-use medical devices are often costly and need to be cleaned and sterilized or disinfected after each use, which can be a labor-intensive and complicated process. Disposable medical devices provide convenience by removing complexity and the potential risks of reprocessing.

One important concern in the healthcare industry today is the occurrence of healthcare acquired infections (HAIs). Infections acquired by a patient in a hospital or other healthcare facility are a significant problem, associated with high healthcare costs and morbidity rates. According to the U.S. Department of Health and Human Services, about one in 25 inpatients have had an infection related to hospital care at any given time, which leads to the loss of tens of thousands of lives and costs the U.S. healthcare system billions of dollars each year.

The Centers for Disease Control and Prevention has called on healthcare organizations to improve infection control and reduce the number of HAIs. To achieve this, hospitals and healthcare facilities are increasingly utilizing disposable medical devices, many of which contain polycarbonate materials.

Material Selection Considerations

For decades, original equipment manufacturers (OEMs) have relied on polycarbonate as a go-to material due to its light weight, transparency, impact resistance, and rigidity. For medical and healthcare OEMs, polycarbonates have the added benefits of helping to meet considerations in disinfectant compatibility, sterilization requirements, biocompatibility, and regulatory fulfillment.

There are a number of material considerations that are important for disposable medical devices, including chemical resistance and biocompatibility. Medical devices often come into contact with a variety of substances from medical tubing, including drugs, IV (intravenous) fluids, and antiseptics. Therefore, it is essential to ensure the chemical compatibility and sufficient chemical resistance in the expected exposure by conducting chemical compatibility tests on specimen bars, molded parts, and end products.

Medical applications that are intended under normal use to be brought into direct contact with the patient's body fluids or tissues, including blood, need to fulfill various regulatory requirements. Manufacturers offer medical grades that meet certain biocompatibility test requirements of USP Plastics Class VI and ISO 10993-1 and that can be considered as potential material candidates for various medical applications. However, the manufacturer of the final end-use product should do further evaluation by testing the final product under actual end-use conditions to determine the suitability of the selected material grade for a specific medical application.

Selecting the appropriate material and grade is certainly important to not only reduce the material cost, but to also increase production efficiency. In many cases, a thinner wall thickness can be an important requirement for medical parts. At the same time, it is equally important to select a technically competent material supplier to support the development stages, including part and mold design and computer-aided engineering (CAE) analysis.

To select the appropriate material grade, OEMs should consider basic properties such as mechanical strength and chemical resistance to maximize balance with flow behavior. Additional considerations are also necessary in order to meet the sterilization and regulatory requirements for the specific medical application. In addition to following the basic plastic design rules and selecting a proper gating location, the use of CAE is recommended, especially for relatively complicated parts.

Medical devices typically require sterilization before use and OEMs have the flexibility to use different sterilization methods for medical-grade polycarbonate that can meet the goal of delivering the customer a sterilized product. The three main sterilization methods for polycarbonate are heat (both steam autoclave and, to a lesser extent, dry heat); ethylene oxide (ETO) gas; and irradiation with high-energy radiation (gamma or electron beam).

Additionally, instruments and components made from high-energy radiation stable grades of polycarbonate have a built-in visual indicator that immediately indicates to the OEM that the part has been sterilized correctly when high-energy radiation sterilization methods are employed. The color of these grades shifts to a neutral tint after sterilization with high-energy radiation. Even with noticeable color shift post sterilization, polycarbonate can demonstrate better property retention than resins that do not show a color shift. This adds another layer of safety and reduces the risk of HAIs.

If there are concerns about the sustainability of disposable medical devices, they can usually be addressed by carefully designing to minimize the amount of materials needed and by implementing thoughtful packaging solutions. The polycarbonate used in disposable medical devices is often recyclable and can be a part of a hospital or healthcare facility's recycling program.

Proven Performance

The body component of the syringe is injection molded with polycarbonate resin, which was chosen because it flows well and is easily released from the mold.

Examples of disposables utilizing polycarbonates illustrate the versatility of this material. One example of polycarbonate use in a disposable surgical device is the Super Staple™ Classic from OEM Metric Medical Devices. This device provides a superior and instantaneous bone compression force required for bone healing. The bone fixation implant is preloaded into an easy-to-use delivery instrument.

For optimum convenience and cost savings, the Super Staple Classic is offered as a sterile, disposable, complete procedure kit. Makrolon® polycarbonate is injection molded to form the housing of the device, which is roughly the size of a syringe. The material was selected because of its high strength, temperature stability, clarity, and biocompatibility.

With the increase in the number of disposable medical devices, polycarbonate materials are also replacing stainless steel. Aware that improperly sterilized stainless steel equipment increases the risks of transferring pathogens from patient to patient, Caltorque Medical Products (CMP), a division of California Torque Products, switched to polycarbonate for its TorqueSafe™ torque-applying instruments used during orthopedic surgery. Traditionally, these instruments contain stainless steel and are cleaned, reprocessed, and recalibrated after each surgical procedure. Now, the device has transitioned to a mostly plastic cost-effective alternative offering the same at-use performance.

Makrolon polycarbonate forms the handles of CMP's TorqueSafe instruments, which are designed for trauma, reconstruction, small bone, cranio maxillofacial fixation, spine, and extremity procedures. The medical-grade polycarbonate offers easy-flow easy-release characteristics and good hydrolysis resistance, and it is biocompatible according to ISO 10993-1 test requirements.

The TorqueSafe instrument is offered in two versions: single-use disposable and multiple-use disposable, which can be used in several surgeries until the proprietary TorqueSafe mechanism disables the instrument, preventing additional use. The multiple-procedure version withstands multiple cleanings and autoclave cycles, but does not need calibration. According to CMP, TorqueSafe instruments enable the OEM to reduce or eliminate the reprocessing cycle cost associated with reusable surgical instruments while offering an instrument that can fit the recycle and repurposing initiatives of hospitals worldwide.

Bio2 Technologies is another company that will soon introduce a disposable alternative to replace stainless steel instruments used in orthopedic implant surgery. Vitrium® Bioactive Glass Implants help the surgeon determine the appropriate implant to achieve the desired correction. Traditionally, stainless steel instruments are used but these instruments are more expensive and must be sterilized before each procedure. Disposable instruments formed from Makrolon Rx1805 polycarbonate offer a more convenient option for hospitals and surgical centers.

Next-Gen Disposables

From surgical instruments to delivering drugs, disposable medical devices help improve healthcare outcomes and support patient treatment. The demand for polycarbonate materials that make disposable medical devices possible will increase as the disposable medical device market grows. Material suppliers will work closely with OEMs to bring new disposable medical devices to market.

This article was written by Lauren Zetts, North America Market Manager, Medical and Consumer Products – Polycarbonates for Covestro, Pittsburgh, PA. Makrolon® is a registered trademark of Covestro Group. For more information, Click Here .