Crystalline system

Engineers at Leeds University have developed a technique to help drug manufacturers reproduce the crystallisation process by using infra-red spectroscopy to monitor chemical saturation in liquids.

Drug compounds are often crystalline, manufactured in batch process systems. Changes such as temperature and cooling rates during the process could change the structure of the crystals produced, which will significantly affect both their performance and physical make-up.

The latest process, developed alongside researchers at Newcastle and Heriot-Watt universities, provides detailed real-time analysis of the chemical process by measuring supersaturation levels to determine when the crystallisation process begins to occur.

Dr Tariq Mahmud from the university’s School of Process, Environmental and Materials Engineering, said: ‘When you cool water the molecules in the water have to get into the right position to begin crystallising into ice crystals and the temperature can have a bearing on the size of ice crystals that are formed. It’s similar with chemicals, although there is a wider range of parameters to take into account.’

The technique will measure the concentration of a chemical in solution using a probe attached to an infra-red spectrometer. The data retrieved will then be combined with statistical data to provide a more detailed analysis of the crystallisation process than has previously been possible.

Dr Mahmud added: ‘Using a chemometric approach enables us to take many more parameters into account, which makes it a more reliable predictor of the optimum concentration levels required to produce a particular crystal structure.

‘By developing tools to increase knowledge about, and monitor, batch process systems, we are providing practical solutions to problems faced by industry on a daily basis. This sort of technological approach to manufacture will help reduce waste – and therefore costs – and could have a significant role to play in increasing the competitiveness of the pharmaceutical sector.’

The technique has received funding from the Engineering and Physical Sciences Research Council (EPSRC) and 10 industrial partners as part of the Chemicals Behaving Badly programme.