A Low-Cost Batteryless Wireless Dosage Sensor for Implantable Drug Delivery

Many chronic medical conditions can be managed by patients taking specific drugs, such as naltrexone for opioid addiction, buprenorphine for chronic pain and insulin for diabetes at specific dose levels on a regular or periodic basis. These drugs are typically delivered via oral, transdermal, or injected means. They usually follow simple first-order drug release kinetics which may pose a significant risk of either undesirable toxicity (overdosing) due to initial concentration peaks arising from burst release or loss of efficacy (underdosing) because of subsequent rapid drug concentration decline below the therapeutic range. Hence it is of great interest to pharmaceutical companies, medical device companies, patients and healthcare organizations to achieve a sustained drug release, ultimately reducing toxicity and increasing efficacy. For example, it has been found that 20 to 40 micro-gram doses of human parathyroid hormone fragment (1-34) [hPTH(1-34)] administered daily for up to two years have resulted in a decrease in the incidence of fractures associated with osteoporosis.

Thanks to rapid advances in microfabrication, RF technology and materials science, implantable drug delivery (IDD) has become very appealing for many types of drug and for treating many chronic diseases. The global market for IDD was worth £9.5 billion in 2015. It is projected that the market size for IDD will increase exponentially over the next decade. IDD offers several unique advantages: i) it localizes the drug delivery, maximizing the efficacy-dose relationship; ii) it reduces toxicity and leads to fewer side effects; iii) it supports the controlled administration of a therapeutic dose at a desirable rate of delivery; and iv) it improves patient compliance by eliminating the chances of missing or erring in a dose.

An IDD device can be classified as either passive or active, depending on whether there is a permanent power source on the device. Passive IDD devices are simple, but lack quantitative feedback from the implant to the external unit after implantation. Thanks to the on-board battery, active devices have higher device intelligence than passive devices. Many active IDD can continuously monitor the drug dosage and send the information wirelessly to an external reader. However, existing sensors in active IDD devices usually require a dedicated readout circuit with the sensor inside the implant, increasing the total size, cost and power consumption of the device.
The proposed technology is similar to the RFID technology for which an external reader interrogates a passive LC resonator sensing tag, wirelessly acquiring the information from the sensor. It requires no battery and is not limited by the types of drug or media surround the drug.

The proposed research is extremely well aligned with the UK government's priority area for industrial strategy on "Leading-edge healthcare and medicine". It also aligns with several high-level initiatives, such as the UK's Life Sciences Industrial Strategy 2017, in which innovative drug and device discovery has been clearly highlighted; the EU's Innovative Medicine Initiative and EU-US Task Force on Biotechnology Research; and WHO's mission to reduce antimicrobial resistance. It also strongly aligns with EPSRC's commitment to promote science for a healthy nation. It will address EPSRC's Healthcare Technologies Grand Challenge on Frontiers on Optimizing Treatment because the proposed batteryless wireless dosage sensing for drug delivery will be a major step towards personalized medicine, significantly reducing the device cost associated with wireless sensing.

The UK is now Europe's largest hub for innovation and development in the healthcare and bioscience sectors and has more than 2000 biotechnology companies. The UK pharmaceutical industry employed 73,000 people in 2017 and contributes £7.5 billion to the economy every year. Advances in medical wireless sensing and drug delivery will further enhance the UK's leading position in the sector and can be a platform technology applied to many drugs and medical conditions.

The proposed technology will directly benefits patients, allowing them to be aware of the drug usage and monitor the drug consumption in unusual conditions. When being combined with existing actuation technologies which drive drug release, the wireless dosage monitoring can provide a close-loop control of drug delivery. It is a major step towards personalized medical tracking and chronic disease management for individual patients. The proposed simple data uplink service makes dosage data available to clinicians and healthcare professionals who can better monitor the drug intake by individual patients.

Outcomes of the project will be disseminated to the wider scientific community and beyond. Findings will be published in high-impact peer-reviewed journals and conferences on both engineering and drug delivery. Novel IP arising from the project will be protected through patent application before publication. The research team will work closely with the UCL Public Engagement Unit (PEU) to design the most suitable forms of public engagement activities, such as exhibitions at the London Science Museum and Medtech Expo, to raise the awareness of and share our research outcomes with people outside academia.

The prestigious Innovation Fellowship will help the PI establish himself as a leading researcher on implantable systems, sensors, and drug delivery devices, expanding his research network and creating more opportunities for collaboration and research exploitation. The PDRA will have the opportunity to work in a multi-disciplinary research team and experience software and hardware development, system prototyping and experiment work. Researchers will benefit from UCL's world-class training and support, such as on research skills and entrepreneurship. The findings of the project will be incorporated into the undergraduate teaching of the PI on electronic circuits and systems.