Two healthcare megatrends are driving global demand for a wide range of pharmaceutical packaging and drug delivery devices. Aging populations and economic gains in developing nations are contributing to a higher use of healthcare products, putting intense pressure on manufacturers to produce significantly greater quantities more quickly. Many companies are looking for new ways to build faster throughput and greater scalability into their supply chains while optimizing costs. One proven approach is replacing traditional vulcanized rubber materials with thermoplastic elastomers (TPEs).

Although widely used in stoppers and septa, caps and closures, syringe plungers and IV bag connectors, vulcanized rubbers can be costly and inconvenient due to the long processing cycle and the need to wash the parts to remove residual chemicals. Replacing rubber with specialized healthcare grades of TPEs streamlines processing and minimizes secondary operations, raising productivity and reducing system costs. In addition to these major manufacturing advantages, TPEs deliver a number of design and usability benefits. Advanced TPEs can make an important contribution to supply chain efficiency, enabling pharmaceutical companies to take full advantage of growing demand for their products. 

Leveraging Growth from Two Healthcare Trends
Two sweeping changes are affecting global demand for pharmaceutical products. The aging population is leading to greater overall consumption of healthcare services and products, with a particular emphasis on treatments for chronic diseases, often administered by patients or caregivers in a home setting. Effective care in the home calls for packaging, device designs and materials suitable for elderly, chronically ill and disabled consumers, making ergonomics, aesthetics and comfort increasingly important. For example, the U.S. Food and Drug Administration’s (FDA) draft guidance1 on design considerations for home-use devices cites sensory perception/tactile sensitivity variations among users as an important feature.

In developing nations, growing affluence and the rise of the middle class are driving expanded use of healthcare services. However, in these low- to middle-income countries, increased availability of medical devices must be paired with affordability. According to a World Health Organization (WHO) bulletin from January 2013,2 “...Radha Basu, director of Santa Clara University’s Frugal Innovation Laboratory in the U.S. state of California, believes that one of the big drivers of change is the increased demand for effective and robust low-cost medical devices from emerging economies, notably China and India.”

To take advantage of the growth generated by these forces, pharmaceutical companies need an efficient and flexible supply chain that can sustain major increases in demand. Two keys to supply chain optimization are higher productivity and streamlined processing, which not only yield greater quantities in a shorter period but can also drive system costs down. New materials can help manufacturers meet these goals. The most innovative solutions, such as medical grade TPEs, also bring other benefits to the table.

Moving Beyond Vulcanized Rubber
For years, vulcanized rubbers have been used in a range of pharmaceutical packaging and drug delivery devices. Although these materials offer cost advantages, processing them presents many drawbacks that can negate the cost benefits. For example, the vulcanization or curing step, not only takes time but also requires chemicals such as sulfur and zinc. Any unreacted chemical agents must be washed away after molding to prevent them from leaching into the pharmaceutical product and potentially interacting with a drug. This post-cure step can lengthen the process by hours and requires environmentally appropriate disposal of the washing agents. In addition, rubber parts typically require de-flashing and often must be assembled using adhesives, adding costs.

Manufacturers can achieve the desirable flexibility, low modulus and soft touch of vulcanized rubber, while adding processing advantages and the potential for recycling, by choosing TPEs. Medical grade TPEs offer a viable alternative to medical grade rubbers. These materials have very low levels of leachables and extractables for safety, and are available in many different formulations to address specific processing and end product requirements. In contrast to the lengthy and complicated processing required for vulcanized rubber components, TPEs feature a faster and simpler system. They are supplied fully formulated to meet the functional demands of the required application. No curing step is required because TPEs combine thermoplastic properties with their elastomeric characteristics, helping manufacturers avoid the time-consuming and environmentally challenging washing step.

Unlike thermoset rubber, TPEs can be injection molded or extruded using high-speed equipment, and can be overmolded onto a substrate in a single operation such as two-shot injection molding or insert molding. Overmolding can eliminate the need for adhesives, helping to promote a seamless, secure bond and enabling part consolidation. With simpler processing and the use of high-speed molding machinery, TPEs can boost production speeds, increase productivity and lower overall system costs. These versatile materials also provide other highly desirable design and usability advantages.
Promoting Ergonomics and Usability

While TPEs range from ultra-soft to rigid and from transparent to opaque, they share three characteristics:  the ability to return to their original shape after being deformed, the ability to be processed as a melt at an elevated temperature and the lack of significant creep. Most TPEs can stretch repeatedly to at least twice their original length, some up to 10 times their length, without significant permanent deformation. TPEs can also be easily colored, and can accept special visual effects for aesthetic appeal and product differentiation; as well as provide a further visual check at the point of care.
Available in a range of hardnesses and capable of providing a customized feel, TPEs are ideal for medical device packaging and for devices that require ergonomic design and excellent usability, particularly for self-care by elderly or disabled users.

The ergonomic value of TPEs can be seen in an award-winning prefilled syringe designed by OXO, a New York-based consumer products brand, for UCB, a global biopharmaceutical leader. This innovative syringe system for home use was developed to help patients suffering with rheumatoid arthritis and takes into account specific dexterity challenges they may encounter when self-administering their medication. Features include a non-slip finger grip and an overmolded ergonomic thumb pad, both molded from PolyOne GLS VersaflexTM TPE, a soft, flexible, non-slip material that enhances ease of use and comfort.

Expanding Design Freedom
TPEs also increase design freedom, which can drive innovation and competitive advantages for pharmaceutical manufacturers. To improve the precision of dosing for liquid medicines, Andwin Scientific, a manufacturer and brand owner of medical and laboratory supplies, conceived the SealSafe® bottle dosing adapter for oral liquid medicines based on a self-sealing septum. A dosing syringe equipped with a bottle adapter allows the person to completely invert the bottle during oral dosing, improving accuracy and enabling every drop of medication to be used. The dosing adapter consists of a cylindrical, polymer shell with the septum at its core. To create the membrane, a custom-formulated TPE from PolyOne GLS is overmolded onto the shell, which also includes flexible fins.

The Andwin Scientific application demonstrates one of the major design features of TPEs:  overmolding onto a plastic substrate instead of using adhesives to join components. Overmolding provides a tough, seamless bond that can be stronger than the two materials themselves. This approach also helps to prevent leaks in medical devices, such as securing the connection between tubing and an IV bag. In one case, a manufacturer of a polypropylene (PP) hose for medical applications, including laser surgery, respiratory care and sleep apnea equipment, selected a thermoplastic vulcanizate (TPV), a type of TPE with a vulcanized dispersed phase, to overmold a cuff on the end of its hoses, providing a quality seal.

A vial stopper for medical applications from a major pharmaceutical manufacturer also showcases the benefits of overmolding. The original part consisted of a PP sleeve that positioned a separate thermoset elastomer button over the vial. Engineers developed a single, part manufactured by overmolding and fuse-bonding a TPE to PP via two-shot injection molding. In addition to halving the number of parts, the fuse bonding reduces the potential for leakage failures.

Pharmaceutical manufacturers have an unparalleled opportunity to drive growth by addressing global demand for their products, which is spiking due to the needs of elderly patients and the demands from middle class consumers in China, India and Brazil, among other nations. New legislation broadening healthcare access, together with continued economic improvements, have the potential to accelerate demand even further. 

Pharmaceutical and medical device companies need new strategies for optimizing supplies of their products so they can meet current requirements and scale up for the future. A simple and effective solution is upgrading from traditional vulcanized rubber with versatile thermoplastic elastomers. The beneficial effects can be far reaching, beginning with a streamlined production process that drives up volume and drives down costs. High-speed injection molding and extrusion capabilities are just the beginning. Manufacturers can avoid toxic materials, multiple secondary operations and complex assembly steps. From a strategic standpoint, TPEs also enable new, integrated designs that reduce supply chain complexity. These materials add further value by promoting ergonomics, ease of use and safety, as well as improved aesthetics for consumer acceptance and brand differentiation. 

Versaflex™ is a trademark of PolyOne GLS.
SealSafe® is a registered trademark of Andwin Scientific.

About the author:
John Voyce is the Marketing Managerin Europe for PolyOne GLS Thermoplastic Elastomers. Voyce has worked at PolyOne for nine years in a variety of roles which include Area Sales Manager, Key Account Manager and Business Development Manager.  
Prior to joining PolyOne, Voyce served as a product development technologist for rigid PVC for injection moulding and extrusion and PVC Plastisols. Voyce has also spent several years in sales for rigid and flexible PVCs and TPEs.