21 August 2013 - A solvent-free, continuous method of producing the more bioavailable form of the anti-malarial drug artemisinin with a longer shelf-life has been developed at the University of Bradford. The research team believes that the patented process could be applied to other drugs too.
The research, published in the Royal Society of Chemistry journal, CrystEngComm, reports the success of using high temperature extrusion to generate and stabilise the lesser-used triclinic crystal form of the drug. There are two main crystal forms of artemisinin. In drug manufacture, the most commonly-used form is orthorhombic but, as it is not particularly bio-available, large amounts are needed to achieve the required effect. The triclinic form is more soluble and has a high dissolution rate, making it more easily absorbed by the body and reducing the amount of the drug required for effectiveness. However, the triclinic form is much less stable in the presence of even small traces of solvents, making it problematic to manufacture.
Funded by the EPSRC’s Science Bridges project, the research was led by Professor Anant Paradkar, Director of the University’s Centre for Pharmaceutical Engineering Science, with support from collaborators in India. A key focus of the Centre for Pharmaceutical Engineering Science is the development of green processing technologies.
“There’s a drive within the pharmaceutical industry to explore unstable forms of drugs, where the most commonly-used stable forms have problems such as low bio-availability, low solubility and manufacturing difficulties,” says Professor Paradkar. “We worked to address this using high temperature extrusion to control the polymorphic transformation of the triclinic form. To our knowledge, this is the first time that this green approach of solvent-free continuous processing using high temperature extrusion for polymorphic transformation has been used.”
The resulting product has been shown to have a much greater shelf-life than the triclinic crystals formed by solvent-based methods, with crystals still stable after one year. “We feel that this method is capable of being scaled-up for high throughput,” says Professor Paradkar. “The method is not specific to artemisinin, but can be applied to many other pharmaceutical drugs, not only making drugs that are more effective in smaller doses, but making drug manufacture more cost-effective.”
- Polymorphic transformation of artemisinin by high temperature extrusion Chaitrali Kulkarni, John Kendrick, Adrian Kelly, Tim Gough, Radha Charan Dash and Anant Paradkar. CrystEngComm 2013, DOI: 10.1039/C3CE40726H
- Founded in 1966, the University of Bradford is one of the UK’s ‘traditional’ universities. It is a research-active institution, with over 80 per cent of our research being rated as either ‘international’ or ‘world-leading’ in the 2008 Research Assessment Exercise (RAE). The University was ranked No 1 for Graduate Employment in the North of England and No 16 in the UK by the Sunday Times University Guide 2013. Known for its strong emphasis on employability skills and knowledge transfer work with businesses, the University has a truly global make up with over 20 per cent of its student population being international. The University is also a leader in sustainable development and education, and is within the top ten greenest universities in the UK, according to the Green League 2012.