
Prototype implantable emergency drug injector by H Lee and his team at Purdue University.
Image Credit: Purdue University
Dr. Hyowon “Hugh” Lee, an assistant professor of biomedical engineering and his team at Purdue University have been developing an interesting implantable drug delivery system. Unlike traditional pumps, this device is meant as a one-time injector for life-saving drugs such as naloxone (opioid antidote) or epinephrine (treatment for anaphylactic reaction).

Purdue researchers are developing a wearable device that would automatically deliver an antidote upon detecting opioid overdose, buying time for emergency services to arrive. (Purdue University image/Jongcheon Lim)
The implantable “A2D2” capsule contains the drug in a capsule that is sealed with a phase-change material. When heated, this material melts and allows the capsule’s payload to be delivered to the body.

Image Credit: Purdue University image/Jongcheon Lim
Activation is accomplished through an external controller that inductively heats a stainless steel plug within the A2D2. The external controller is meant to have the means to detect an opioid overdose by monitoring the patient’s ECG and respiration, thus allowing for fully-automatic delivery of the life-saving antidote.

Conceptual view of the external controller for the implantable emergency drug injector being developed at Purdue University.
Image Credit: Purdue University
According to the paper “Simple minimally-invasive automatic antidote delivery device (A2D2) towards closed-loop reversal of opioid overdose,” the device can release 1.9 mg of powdered naloxone drug within 60 s and up to 8.8 mg in 600 s.
The device is just in its feasibility stage. The paper shows that the A2D2 prototype leaked 1.75% of its drug payload over the course of 1000 h of simulated implantation. As such, the researchers acknowledge that further development and testing of the device is needed to verify its long-term stability in-vivo. In addition, further research is required in the development of a reliable controller capable of detecting an opioid overdose and automatically releasing the drug.