TECHNOLOGY LEADERS: Materials/Coatings/Adhesives

According to the United Nations Department of Economic and Social Affairs—Population Division, the world’s population is projected to skyrocket from approximately 7 billion in 2012, to nearly 10 billion by 2050. In addition, according to the United Nations Fund for Population Activities (UNFPA), the worldwide population aged 60 and over is projected to more than double during that same time from 810 million to approximately 2 billion. The question is how will this impact society?

Fig. 1 – Population aged 60 or over: world and development regions, 1950-2050. (Source: United Nations Department of Economic and Social Affairs – Population Division “World Population Aging 1950-2050”)

To put things into perspective, according to United Nations estimates, the global population in 1950 was around 2.6 billion. With current population trends and projections, that number will have nearly quadrupled within just two generations. In 1950, the global population of those aged 60 and over was approximately 200 million, or about 8 percent. By 2050, that percentage will reach 2 billion or 22 percent of the global population. (See Figure 1)

The numbers paint a stark picture—the world is in the midst of an unprecedented escalation in population that will put an enormous strain on the world’s stressed resources including food and water, housing, and energy supplies. In addition, changes in global demographics—such as a population shift towards urban city centers—will exacerbate existing healthcare problems, including the occurrence of both communicable and non-communicable diseases. As a simultaneously growing and aging population requires treatment, a ripple effect will be created across the pharmaceutical and medical device industries in the demand for safe and effective drug-delivery solutions.

Drug-Delivery Device Trends

Extreme global population growth coupled with an increasing number of people over the age of 60 requiring continual care is creating a very real need for the next generation of drug-delivery devices, as well as the innovative highperformance materials that help make them work. This is driving tangible changes in technology that exist today, as manufacturers bring advanced drug-delivery devices with enhanced performance properties to market, helping meet the many challenges faced by patients and over-taxed healthcare systems throughout the world.

One primary challenge facing healthcare providers is that of available space and resources. While the global population has increased, the number of hospital beds, staff, and equipment has not, creating a need for safe, effective, and efficient treatment options for patient use at home, as well as use in remote locations throughout the world where hospital care is not readily available. As a direct result, the medical device market is already seeing several emerging trends in the area of drug-delivery devices. We are seeing a wave of innovation in material science and manufacturing capabilities, allowing medical device makers to produce safe and effective devices in high volume.

New Material Technology for Injector Devices

According to the United Nations Department of Economic and Social Affairs (DESA) – Population Division, rates of various non-communicable diseases are rising as the global population both grows and ages simultaneously. To combat this, an increasing number of injectable drugs are being developed to treat such chronic conditions as diabetes, rheumatoid arthritis (RA), and osteoporosis. Beyond the treatment of chronic conditions, injector devices are also being used in the fast and effective delivery of anti-nerve agents and anaphylactic shock treatment where speed and intuitive use can be a matter of life and death. What we are seeing is an increased focus on the safety and effectiveness of delivery devices such as injection pens, auto-injectors, and safety syringes.

Fig. 2 – Compounds being used for injection pens are being refined for better safety, and can be laser markable.

Injection pens are simpler, more durable, and more convenient to use than the traditional vial/syringe method. They can be configured for single-use and combined with advanced sharps technology to reduce the pain of injection and help to increase patient compliance. New materials and process technologies are being used during the material selection and design phases to make them safer to use. (See Figure 2)

For example, patient-operated injection pens are being developed with laser marking to ensure accurate dosage, making them easier and safer to use. This type of marking is more permanent and solvent resistant than conventional hot stamping or pad printing. In order to take advantage of laser marking technology, select additives are incorporated into thermoplastic compounds that cause a photochemical reaction on the surface of the part when exposed to the laser beam.

Materials science is also being applied to improve patient interaction with injector devices. Most, if not all, injector devices come into direct contact with the patient in one way or another. Pen housings made with biocompatible polymer formulations prevent irritation and avoid potential for allergic or sensitization reactions.

In addition to population growth trends driving material and process innovation, strict regulatory requirements—particularly in the US—are spurring advances in safety syringes, worldwide. The Occupational Safety and Health Association (OSHA) Bloodborne Pathogens Standard (29 CFR 1910.1030) and a related field directive, Inspection Procedures for the Occupational Exposure to Bloodborne Pathogens Standard (CPL 2-2.44, November 5, 1999) require the combined use of engineering and workplace controls to prevent injury. This means that in addition to safety precautions implemented in the workplace, safety must also be incorporated into the design stage of medical device manufacturing, including material selection.

Sharps safety is top-of-mind for any healthcare provider, and safety syringes are being designed with this in mind. The use of internally lubricated plastic compounds to reduce stiction in injector devices with metal-on-plastic and plastic-on-plastic contact results in less friction and improved “glide factor” for quick and easy sharp covering or retraction to prevent secondary needle sticks. In addition, polymers are being formulated with internal lubrication for use in auto-injectors and injector pens, delivering a pre-measured dose with spring force and a desired injection speed. This internal lubricity avoids sticking, allowing the proper dose to be safely and effectively delivered to the patient.

Equally important to patient safety is proper device identification and usage. Plastic compounds with biocompatible, pre-tested additives are being used to develop color-coded devices that indicate type function and volume for split-second identification during medical emergency procedures. Color is also be used to represent brand identity in an extremely competitive medical industry marketplace.

Inhaler Enhancements

High-performance inhalers are being used to treat an increasing number of respiratory diseases in addition to asthma and Chronic Obstructive Pulmonary Disease (COPD). The next generation of inhalers are capable of delivering influenza vaccines, anti-hypertensive medications, anti-inflammatories, pain medication, and antimicrobials into the blood stream rapidly. They feature improved drug-delivery accuracy for both powdered and aerosol drug formulations used in dry powder inhalers (DPIs) and pressurized metered dose inhalers (pMDIs).

Because they are inherently insulative, plastics and plastic components can accumulate an electrostatic charge to their surface, attracting dust, or in the case of medical devices, medicine particulates. This static attraction can cause drug formulations to adhere to a plastic drug flow path, preventing DPIs and pMDIs from delivering a full or accurate dose. However, there are conductive plastic solutions that eliminate the static charge.

By blending plastic resins with inherently dissipative polymers (IDPs) can create clear anti-static or static-dissipative compounds that reduce surface and volume resistivity. Permanently anti-static compounds based on acrylic (PMMA), polypropylene (PP), clear acrylonitrile butadiene styrene (ABS), and polycarbonate (PC)/ABS are commonly used. This co-continuous polymer morphology allows electricity to dissipate, independent of moisture content in the air, providing electrostatic discharge (ESD) protection. This prevents small drug and carrier particles from sticking to the drug flow path, resulting in improved drug throughput by more than 80 percent, increasing dosage accuracy for single and multidose inhalers.

Advanced Patch and Pump Technology

Transdermal patches are best known for their use in the delivery of addiction cessation medication, birth control, and low testosterone (“Low T”) treatments. Transdermal patch and subcutaneous pump technology have combined to form a hybrid that uses integrated electronics to provide remote monitoring and programmable measured dosage for a higher level of patient safety. In addition, remote monitoring can be used to determine drug and/or delivery device efficacy through the analysis of outcome data. Patch-pump hybrid devices with these innovative electronic capabilities are seeing increased use in the delivery of drugs for chronic pain and disease.

Fig. 3 – The housing and internal chassis of an insulin pump are enhanced with the use of thermoplastic compounds.

Also available are state-of-the-art patch-pumps with safe and easy-to-use hand held controls for increased patient compliance and minimal potential for human error. In an effort to increase comfort and ease-of-use, patch-pumps are being developed with specialty compounds used to make environmental seals that allow for continued use while bathing and exposure to environmental elements. In addition, patch-pump devices are being made with non-rigid elastomeric materials to achieve a “soft-touch” feel for increased patient comfort (See Figure 3).

Drug-delivery pump and compressor parts that face continuous movement and pressure challenges can be made with durable plastic materials have a high Limiting Pressure Velocity (LPV) point and/or good burst pressure qualities. High performance plastic materials can be compared prior to specification and incorporated into device design to ensure quiet operation and extended product lifecycle. The right materials can also be used to design an extremely durable compressor housing that not only features a high level chemical resistance to harsh cleansers and withstand constant loads without breaking, but provides quiet operation using elastomers for sound-dampening gaskets and liners.

With cutting-edge medical devices made using advanced materials and manufacturing processes, drug-delivery device trends are the driving force behind many recent technological innovations. Using state-of-the-art polymers and manufacturing processes, manufacturers are pushing the envelope of drug-delivery, creating devices with improved function, as well as reduced part count and size.

For example, Laser Direct Structuring (LDS) is being used to embed circuitry into smaller drug-delivery device components. In an injection molding process utilizing a thermoplastic material combined with laser-activated additives, a single component is injection molded, laser etched, and plated with metallized circuit tracks. These miniature metallized circuit tracks allow for the fusion of thermoplastics and small electronics devices.

In transdermal delivery devices, LDS technology can help ensure a high level of remote drug security with improved patient safety and monitoring. LDS can also allow for miniaturized components that ultimately mean smaller, less obtrusive medical devices. For future medical devices, the sky is the limit for plug and play designs that incorporate smart sensing and transmitting capabilities.

LDS technology can add plug and play smart features to advanced drug-delivery devices, such as time and temperature sensing, Wi-Fi, radio, and/or audio transmitting. These functionalities go well beyond just patch and pumps. Imagine injection pens with built-in patient monitoring to help improve compliance and safety, or pens that are able to provide real-time shared data and analysis on disease-specific social networking sites.

Conclusion

Global population growth has reached unprecedented levels and shows no sign of slowing; coupled with the increased number of people over the age of 60, adequate healthcare is a major concern. The skyrocketing rates of chronic health conditions, such as diabetes and heart disease, have created a glaring need for safe, effective, and more accessible treatment options.

The technology to meet these challenges exists in the latest generation of drug-delivery devices such as injectors, inhalers, and transdermal patches and subcutaneous pumps, made possible by thermoplastic materials that provide vast performance improvements. The technology exists to design injection pens, auto-injectors and safety syringes with increased ease-of-use and safety.

Present-day advances in materials science allow for clear anti-static polymers that ensure drug particulates do not stick to the drug-delivery path for safe and accurate dosage. Innovative manufacturing processes, such as LDS, are enabling smaller and smarter medical devices that provide increased safety and can help ensure patient compliance. While the population explosion may put a strain on many areas of everyday life, medical device manufacturers and their material suppliers have responded in kind, taking the industry to new and exciting heights to meet the need for better healthcare solutions head on.

This article was written by Josh Blackmore, Global Healthcare Market Manager, RTP Company, Winona, MN. For more information, Click Here .

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Medical Design Briefs Magazine

This article first appeared in the April, 2016 issue of Medical Design Briefs Magazine.

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