Scientists Develop a Long-Lasting Nano-Painkiller which is Less Addictive than Regular Painkillers

The so-called opioid epidemic which recently developed in the United States and Canada has put pressure on researchers to come up with effective socio-political measures and pharmaceutical alternatives to addictive, yet easily accessible, painkillers that people have been overusing en masse.

Now, writing in the prestigious journal Science Advances, a group of researchers from the Université Paris-Saclay and Université Paris Descartes report on the development of a “nano-painkiller” shown to work longer and form less addictive behaviours in rodents.

According to the authors themselves, the “study opens a new exciting perspective for an efficient treatment of intense pain, which evades the severe side effects associated with morphine or related synthetic opioids”.

In the study, the research area which  the group chose to attack was the theoretical possibility of modelling drugs after peptides that occur naturally in the body and bind to opioid receptors (such as enkephalin). Up till now, however, the obstacle on the road to such drugs was the impermeability of the blood-brain barrier.

As a work-around, the researchers equipped a lipid called squalene with a dose of Leu-enkephalin neuropeptides (an impressive achievement considering the latter’s instability) and injected the resulting mixture directly into the body sites where pain was localised, which, in this case, were the painfully swollen paws of a group of unlucky mice.

The core idea was to test whether the compound, delivered right into the peripheral nervous system, rather than the brain, would be effective at reducing pain. To see if the “nano-painkiller” had any effect either way, the group applied heat to the painful areas of their subjects’ bodies and observed their reactions.

In this case, the less reactivity, the better, as that would indicate lowered pain levels – which is exactly what the authors of the paper found. Mice injected with the new painkiller took longer to withdraw their paws from the painful stimulus, proving the drug’s efficacy.

Further testing also showed it to be longer-lasting and, given the lack of interaction with the brain, likely not addictive, or at least much less so.

Before commencing human trials, the team will now move on to experiments with other animals, and try to discover a way to sterilise the drug without destroying it.

Sources: paper, med.news.am.