Cheap malaria drug hope for millions

PUBLISHED : Saturday, 14 July, 2012, 12:00am
UPDATED : Saturday, 14 July, 2012, 12:00am


A team of Shanghai-based scientists say they have discovered a novel method of developing anti-malaria drugs far more cheaply and on a much larger scale, with the potential to benefit hundreds of millions of patients, especially those in Africa.

Since the beginning of this century, the World Health Organisation has recommended artemisinin combination therapies as the most effective treatment for malaria.

However, drugs made of artemisinin are very expensive because the supply of sweet wormwood, a herbal plant grown widely in China and several Southeast Asian countries, from which artemisinin is extracted has remained limited and the extraction process is complicated.

Dr Zhang Wanbin , from the school of chemistry and chemical engineering at Shanghai Jiaotong University, said light was needed in the current method of synthesising artemisinin, which quite a few scientists had grasped, and that had created a bottleneck in expanding the production of artemisinin.

'They can't use large-volume containers [in extracting artemisinin], because the liquid at the middle or bottom of the big containers won't be affected by the light,' Zhang said.

He had been trying for seven years to find a way to produce artemisinin without using light before identifying a catalyst which could boost artemisinin production by 50 per cent and slash costs by more than half.

Zhang refused to reveal any information about the catalyst, but said the synthesising method was simple and productive, with the extraction rate - the percentage of artemisinin extracted from dihydroartemisinic acid, a chemical obtained in the middle of the process - being around 60 per cent.

That is higher than the rate achieved by German scientist Peter Seeberger, from the Max Planck Institute of Colloids and Interfaces in Potsdam, who announced in January that they had discovered a simple, cost-effective way of synthesising artemisinin from the waste products of sweet wormwood.

The extraction rate in Seeberger's experiment was 39 per cent. Seeberger claimed that his method could make 800 grams of artemisinin a day, but Zhang said that because light was still essential in Seeberger's method, it would not be possible to scale up production any further.

Zhang said his method could be turned into a large-scale manufacturing processwhere the extraction rate would be even higher.

The raw materials in his method could be byproducts of producing artemisinin, such as artemisinic acid, which are usually dumped, he said. Simple sugars such as glucose could also be used as the raw material, he said, making the artemisinin produced far more affordable than in present drugs.

When Zhang's discovery was announced early this month, the share price of one of the main domestic malaria drug manufacturers, Kunming Pharmaceutical, dropped by almost its 10 per cent daily trading limit on the Shanghai Stock Exchange. It obtains its artemisinin from sweet wormwood, not chemical synthesis.

Zhang is now applying for international patents for his discovery.

Dr Yu Xinbing , a top expert on malaria from Guangzhou's Sun Yat-sen University, said he was not sure if Zhang's discovery would be a real breakthrough because the artemisinin produced had not been used in clinical trials.

He said it was not easy to conduct such tests in China because it had seen just 4,100 cases of malaria in the past four years.

The WHO says 300 million to 500 million people around the world contract malaria every year and an estimated one million - mostly children in Africa - die of this illness due to a lack of useful medicines such as artemisinin.