Closed-loop system offers promise of automated overdose therapy

The need to quickly administer naloxone to counter opioid overdoses has spurred innovation in drug delivery for years, with intramuscular, subcutaneous and nasal doses all used, but the approaches all rely on there being someone present to administer the countermeasure. Recognizing that limitation, a team at the University of Washington has developed an automated naloxone delivery system.

Writing in the journal Scientific Reports, the researchers describe the use of West Pharmaceutical Services’ SmartDose wearable injection system as the basis for a closed-loop naloxone technology.  The researchers combined SmartDose, which normally delivers a dose when the wearer presses a button, with an accelerometer-based sensor patch and an actuator. The sensor detects the overdose, and the actuator activates the injector system. 

“In this work, we develop a closed-loop naloxone injector system that can identify real-world and simulated opioid-induced apneas and deliver naloxone subcutaneously. Such a system has the potential to readily reverse overdoses particularly when the event is unwitnessed,” the authors wrote.

The researchers have tested the system in humans. At a supervised injection facility, the researchers enrolled 25 people to wear the device while administering opioids. The study found the breathing data collected by the system corresponded to those captured by a breathing belt, providing evidence of the potential for the experimental technology to detect overdoses.

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As un-indicated naloxone administration can cause withdrawal, the injection facility study didn’t use the drug, instead only assessing the ability of the system to track breathing. The researchers ran a separate study to assess whether the actuator and injector work.  

In that study, participants held their breath to simulate what happens during an opioid overdose. The injection system failed to activate in the first two subjects, but the success rate increased after the device was repositioned in line with the instructions for use. The system activated the first time in 15 of the next 18 participants.