Chemist finds way forward on 'retro' route

Irish researchers have discovered a method of synthesising a drug that may block animal diseases in the tropics

Irish researchers have discovered a method of synthesising a drug that may block animal diseases in the tropics. Dick Ahlstrom reports

A chemist at IT Tallaght has helped bring a potentially valuable new anti-malarial drug from the lab and into field trials in less than three years. He and a research student synthesised the compound identified by a pharmaceutical firm and the animal drug is now undergoing tests in East Africa.

It started several years ago when researcher Michael Courtney of Tallaght's department of applied science started scouting for collaborations with industrial partners and established contact with a animal pharmaceutical company with offices in Dublin.

"I have a research background in chemical synthesis and also the pharmaceutical industry," says Courtney. It is standard practice for the institute's academics to look for industrial linkages. "Our remit here is to develop collaborations with outside companies," he says.

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The company gave him a molecule of interest to them. It knew that the molecule had interesting features and believed, based on previous findings, that it might be useful against certain tropical animal diseases, Courtney explains.

The problem was while the company had the molecule and a means of doing trials of the drug in East Africa, it lacked the expertise to produce the drug, to synthesise it in the lab. "They wanted a chemist to go ahead and make it. I developed a pathway to it," says Courtney.

He mapped out a way to produce the molecule and then got fourth-year BSc student Tracy Doyle to oversee the synthesis and confirm the resultant compound was indeed the drug of interest.

Fourth years typically put together final-year project work that carries over several months. Courtney says he wanted to come up with an industrial-based project that would have much relevance after graduation.

Courtney devised a production route to the drug by working backwards in what is known as "retro-synthetic analysis". A similar method was used to synthesise the breast cancer drug taxol, he says. You step backwards breaking the target molecule into smaller precursor molecules until the complete route to the drug is revealed. Obvious break points present themselves to a chemist, for example a carbon nitrogen bond that provides a break to smaller molecules.

The real trick is to find a quick and simple route to the finished drug with as few steps as possible, says Courtney. "You don't want too many pathways to it, it would cost too much. You want to cut down on the steps. You want your product to fall out of solution," he says.

Simplicity in synthesis usually means it is easier to separate and purify the finished drug, he adds. His own synthesis has only two steps, both done in the one "pot".

"We got the compound and we made an initial 10g of it," he says. They then bumped production up to 100g, handing this over to the company so that field trials could begin.

"We are waiting on results from these trials to see what happens next," Courtney says. "They are getting encouraging results back and the latest results are very encouraging."

This initial collaboration went well and other projects are now under way. It works for both parties, he believes. The company gets help with drug synthesis and Courtney has a real-world project suited to fourth-year research students.