In a first, scientists have developed a drug activated by light which has therapeutic applications for the treatment of pain.

The new "photo-drug" -- JF-NP-26 -- is a molecule that can be specifically activated at any wished moment (that is, with a high spatiotemporal resolution) with light, the researchers said. "This is the first light-activated drug designed for the treatment of pain in vivo with animal models," said Francisco Ciruela, Professor at the University of Barcelona. 

JF-NP-26 is activated when receiving light -- using an optical fibre -- of a suitable wavelength and with an exact precision on the target tissue (brain, skin, articulations, etc). The drug does not show toxic or unwanted effects even if the dose is high in short-length studies on animals. The discovery, published in the journal eLife, will overcome the problems faced with the uses and effects of current drugs such as the slow and inexact distribution of the drug, lack of spatiotemporal traits in the organism and difficulties in the dose adjustments, the researchers said.

JF-NP-26's lightening includes a treatment on the molecule that releases the active molecule (raseglurant) that blocks the metabotropic glutamate type 5 (mGlu5) receptor, found in lots of neuronal functions such as the spread of neuronal pain.  Blocking this receptor allows preventing the pain from spreading into the brain. This can be produced both due to the outlying neurones and the central nervous system (brain) and create, in both cases, an analgesic effect as a result. "The molecule created by the action of light, the raseglurant, does not belong to any group of drugs from the classic anti-pain list of drugs: non-steroidal anti-inflammatory drugs or NSAID (paracetamol, ibuprofen, etc.) and opioids (morphine, phentanyl)," Ciruela said.