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Single-Dose, Longer Lasting Antidote May Prevent Overdoses

Using polymer nanoparticles, researchers are developing a better-acting emergency alternative from naloxone

A PPM Brief

Synthetic opioids account for a growing number of opioid overdose deaths in the US; according to the CDC, heroin, oxycodone and fentanyl were implicated in approximately 47,000 overdose deaths in 2017. For example, fentanyl's effects are long lasting, and overdoses can occur even with small doses; fentanyl is absorbed into fat tissue, which prevents metabolization, then slowly releases causing effects for several hours.

Naloxone, on the other hand, is an opioid overdose medication that requires repeated injections, as it may not last long enough in the body to fully counter drugs some synthetic opioids. A mu opioid receptor (MOR) antagonist, naloxone only stays in the system between 30 minutes to up to an hour. This duration requires repeated doses to be taken by the patient to help them recover. However, according to a release,1 not all patients may want to undergo the entire treatment, which may cause them to succumb to an overdose after the naloxone is metabolized.

In response, researchers are working to develop single-dose, longer-lasting opioid emergency overdose medications using polymer nanoparticles, according to research recently presented2 at the 2019 American Chemical Society (ACS) National Meeting.

Using polymer nanoparticles, researchers are developing a better-acting emergency alternative from naloxone. (Source: 123RF)

So far, they have developed a drug delivery system intended to ensure that a steady, sufficient dose of the antagonist is delivered over 24 hours, reacting the multi-ringed chemical structure of naloxone with polylactic acid (PLA) to create a polymer. Researchers then prepared covalent nanoparticles (CNPs) by adding the polymer to a solution of polyvinyl alcohol, using a variety of analytical methods to purify and analyze the resulting particles. In mice, the new nanoparticle delivery system counteracted the pain-relieving effects of morphine, for example, for up to 96 hours after administering a single dose of the antidote.3

Although performed in mice, future studies will include animal models that more closely simulate how humans metabolize opioids. The researchers are also planning to investigate how particle size impacts naloxone’s release from the nanoparticle.3

Naloxone Manufacturer Response

In response to these findings, a representative from Adapt Pharma (makers of Narcan, a naloxone nasal spray) told PPM that, “Repeated dosing is often seen when the patient is under the care of a medical professional who is titrating the naloxone administration to use the minimal dose necessary to prevent withdrawal symptoms. It is important to understand that the goal of an opioid antidote is not to ‘fully counter’ or complete neurological reorientation, but simply to reverse the life threatening airway concern, allowing for the victim to breathe on their own.”

They continued, “Also important when administering naloxone: the dose, route, and concentration significantly impact plasma levels. Only recently has the NIH released data concerning the pharmacokinetics of newer FDA-approved naloxone devices that focus on providing a higher dose of naloxone.”

A representative from Kaleo (makers of Evzio, a naloxone autoinjector) also told PPM that, “Multiple doses of naloxone may need to be administered per overdose event because of fentanyl’s high potency relative to other opioids.”

Last updated on: May 10, 2019
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