Medical Plastics Technology and Applications

Medical science continues to advance in both disease treatment strategies and the understanding of medical conditions. Concurrent with these advances in health care, there have been several groundbreaking innovations in medical device manufacturing which have helped in improving patient outcomes. The global market for medical devices is estimated to be around $700 billion. With a rapidly aging population, greater governmental interventions and newer emerging markets, the worldwide medical devices market is expected to grow at a rate of 6% per annum for years 2023-2028 (Ref: The Global Market for Medical Devices,13th Edition – Kalorama information). More than half of the market for medical devices comprises the market for implantable medical devices.

The market size of the medical devices sector in India market in India was estimated to be worth $11 billion in 2018 (Ref: Invest India, GOI website). This figure is considerably small given the size and population of India, however, the growth rate over the coming years is expected to be more than double the global growth rate. India is the fourth largest market for medical devices in Asia with an estimated growth potential of around 30% per annum. The expansion scope of the market has currently been impeded partly due to the low per capita spend by the government on health care; another significant obstacle cited in the growth of the market is the lack of indigenous manufacturing.

Plastics constitute an important part of medical devices and the global market for plastics in medical devices is said to be close to $24 billion (Ref: Medical Plastics News, Feb. 2024). This figure includes plastics usage in everything from devices to diagnostics to packaging. With growth foreseen in the devices market, the growth in plastics usage in the devices should at least match that growth. Within the medical devices sector, about half of the market for plastics is in the area of implantable devices.

The nature and properties of plastics has a critical role to play in the correct functioning of a device. Very often the selection of the plastic can dictate the efficacy of the device and the treatment of the disease. Unfortunately, during the design process of medical devices, the role of plastics is quite often either ignored or not properly understood. This necessitates the coalescing of diverse experts including plastics professionals, polymer scientists and medical device design experts in order to exploit the full potential of plastics and facilitate effective treatment of medical conditions.

Medical Devices and Plastics
Plastics have an inherent advantage over traditionally used materials, such as glass and metals, in medical devices. Plastics are lightweight, inexpensive and often compatible with bodily fluids. Most plastics are also comparable in density to the body and thus are easier to be incorporated into the body. They, for the most part, also have a high degree of resistance to chemicals, both natural and synthetic, that make them suitable to be used in medical applications.

Plastics can also be formulated with a myriad of different chemistries. They can be soft or hard, elastomeric or rigid, thermoplastic or thermoset etc.

They can also be formulated as biologically stable or degradable. A stable formulation is one that can resist the action of body fluids and can be inert, making them suitable for the construction of long term implants. A degradable formulation, on the other hand, can be broken down into easily digestible and harmless elements over time. The degradation can be programmed to occur either at a specific time or upon a specific action. This makes biodegradable plastics attractive options in areas such as drug-device combinations and regenerative medicine.

The use of plastics in medical applications spans a wide spectrum of applications. Many plastics form a part of medical disposables such as wipes, bandages, syringes, tubes, blood bags, packaging materials etc. As the name suggests, these are discarded after a single use in a medical procedure. They do come in short-term contact with medicines and/or the human body.

The use of plastics has revolutionized the area of medical diagnostics. Whether it be in simple blood pressure measurement devices or the much more complex Magnetic Resonance Imaging (MRI) machines, plastic materials offer many advantages in the construction of this equipment such as design flexibility, light weight, robustness etc., enabling doctors to diagnose the patient’s condition accurately and monitor the progress of any condition. Often these diagnostic equipment work outside the body and remain external.

The majority of medical devices are made to be implantable systems. These devices are implanted inside the human body and perform critical functions either in the area of drug delivery or regulation of some bodily function. Plastics form the core of many of these devices, and the properties of the plastic material allow greater functionality of the device.

The implantable devices are further divided into short term implantable and long term implantable devices depending on the duration of the dwell time of the implantable device inside the body. Most devices having a dwell time of less than 90 days are classified as short-term implants. Biological stability becomes an important consideration for long term implantables.

Figure 1: Illustration of a cardiac rhythm monitoring device
Stents are metallic wire structures that are used to open up clogged arteries. Stents are frequently coated with polymer solutions incorporating drugs.

Figure 2: Illustration of Neurological Devices, on the left, a Deep Brain Stimulation (DBS) device for Parkinson’s disease and on the right a ventricular shunt for hydrocephalus.

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Author
Ajay D Padsalgikar, (Ph.D. California,USA)
Trainer, Polymerupdate Academy