Microreactors can be a powerful tool for product synthesis in the pharmaceutical industry, say Swiss scientists. Their application of microreactor technology to an amide bond formation reaction illustrates this.

Peter Seeberger and colleagues from the Swiss Federal Institute of Technology, Zurich, showed that their method can cope with a range of substrates, and applied it to the synthesis of two pharmaceutically active compounds. They claim that the microreactor-based technique is faster and safer than traditional methods, and that scale-up to bulk synthesis level is not a problem.

Microreactors are a potential tool for the pharmaceutical industry © Astrazeneca

'One can think of a microreactor as a small pipe,' explained Seeberger. 'Chemicals are pumped through the pipe and additional inlets can be used to add reagents.' Microreactors allow fast mixing, quick and even heating, and the generation of high pressures. Together this makes for short reaction times; Seeberger's amide bond formation was completed within two minutes, compared to four to sixteen hours using conventional methods. In addition, microreactor systems are safer because the small reaction volumes mean that any hazardous intermediates are formed only in small amounts.

Steve Haswell, an expert in microreactor chemistry from the University of Hull, UK, said that microreactor technology has great potential for industry. Possible applications are reaction optimisation, library building, and safe and efficient product production, he said. The type of work performed by Seeberger 'should make medicinal chemists sit up and look seriously at the contribution microreactor technology has to offer,' said Haswell.

To illustrate the technique's versatility, Seeberger's group is working on applying microreactors for fluorinations and in radical and photochemistry. The group also has close collaborations with industry to look at real-life problems that microreactors could be used to solve. 'Industry is getting into this technology big-time,' said Seeberger.

Danièle Gibney