Toxic algae could be used as an anaesthetic

Work which could see algae used as a local anaesthetic is a step closer to reality, with Nelson scientists discovering a way to produce the toxin needed at scale.

A partnership between the Government and Cawthron Institute in Nelson has delivered a breakthrough in producing a potent ingredient for the world’s first algae-based pain medication, Minister of Agriculture Damien O’Connor announced.

Scientists at the institute have developed a reliable and commercially-scaleable process for producing neosaxitoxin, a shellfish toxin found in New Zealand marine microalgae, Alexandrium pacificum.

A neosaxitoxin-based local anaesthetic has been under development for more than a decade, but progress has been slow due to poor access to the pure compound – until now.

The algae produce a number of similar toxins, including neosaxitoxin. But this only occurs in small amounts, and is ‘‘very complex’’ to purify, Cawthron Institute science impact manager Dr Johan Svenson said.

However, they’ve found that another toxin, GTX-1,4 – naturally produced in much higher quantities – can be converted to neosaxitoxin in a ‘‘one-step chemical reaction’’, and processed into the active pharmaceutical ingredient required.

Their scaleable method is capable of producing ‘‘lots’’ of the stuff, though they are only set up to do about 10 grams a year at this stage. Once fully set up, the process would be capable of delivering 100 grams, Svenson said. While grams may sound small-scale, he estimated you would need about half-a-kilogram of the compound for initial global demand – about ‘‘a block of butter’’. Svenson said scientists had known about the role neosaxitoxin could play in this space for years, with results from the first human trials published back in 2007 – but their solution for production had now ‘‘allowed it to move on’’.

Svenson said neosaxitoxin had a number of benefits.

In trials, when given as an injection with an existing local anaesthetic, bupivacaine, and adrenaline (to prevent distribution around the body) neosaxitoxin provided prolonged pain relief.

Svenson said this could result in less post-operative care needed, less need for infusion pumps and catheters, reduced length of hospital stay, and a reduced need for opioids.

‘‘Surgeons have been blown away with what it can do,’’ he said. The institute is now looking to line up a partnership for phase two trials. ‘‘We could potentially have a New Zealand algal-based local anaesthetic on the global market.’’