A drug lab used by Zhang Zhengbo, a former chemistry professor in Wuhan, Hubei province.Provided To China Daily

Lucrative business

A number of Chinese chemistry professionals have been unable to resist the lucrative business opportunities offered by NPS, which, although widely abused in other countries, are almost unknown in China. That means some of them have slipped below the radar of the nation's drug authorities, according to Hua, from the ministry.

Zhang Zhengbo, 45, a former chemistry professor at Huazhong University of Science and Technology in Wuhan, capital of Hubei province, used to be one of China's leading manufacturers of NPS. During his time as a visiting scholar in Australia, Zhang discovered that some countries have huge markets for NPS, and realized that some of the new drugs widely abused overseas were not classed as controlled substances in China.

The 45-year-old and Yang Zhaohui, a former classmate, established a chemical company. They registered as a producer of pharmaceutical intermediates, but instead manufactured methcathinone and sold it in the United States and Europe under the guise of regular chemical products.

In June 2015, Zhang and seven of his employees were arrested and charged with selling more than 300 kg of methcathinone to buyers overseas. The case has been handed over to the prosecuting authorities.

Ministry in action

At present, there are no coordinated international controls on NPS, although several countries have established permanent measures for cracking down on certain substances and others have issued temporary bans.

In recent years, the Ministry of Public Security has stepped up international collaboration efforts to crack down on the production of NPS.

In Zhang's case, the ministry contacted authorities in more than 20 countries and reported 1,144 clues that will assist in their investigations of cases within their jurisdictions.

In the latest move, the ministry has added four types of synthetic opioids - including carfentanyl, a widely used elephant tranquilizer - to its list of controlled substances.

On March 1, four types of fentanyl-based substances were added to the list of Non-pharmaceutical Narcotic Drugs and Psychotropic Drugs under Control, raising the number of controlled substances in China to 134.

Last year, police found 66 samples of fentanyl-based substances nationwide, a marked rise from the six unearthed from 2012 to 2015.

"More than 10 people suspected of producing NPS have been detained and more than 800 kg of substances has been seized since the beginning of last year. More than 1 metric ton of these, as yet, uncontrolled substances was also seized," said Yu Haibin, head of the department at the ministry that is tasked with curbing the production of illicit drugs.

However, a lack of testing equipment outside of big cities means the police face challenges uncovering NPS abuse.

According to Hua, most local police stations lack equipment to test for NPS, so when police officers decide to test people suspected of using drugs in a public place, they have to collect urine samples and then send them to the ministry's national-level laboratory.

"It takes time to send the results back to the local police, and it takes even longer to enact legislation to ban newly discovered substances," he said.

"In addition, simply by altering the chemical structure of an existing substance, a new psychoactive substance can be produced to circumvent the controls on drugs," he noted, adding that when one drug becomes subject to strict controls, a new, modified substance can quickly be created by fast-acting chemists looking to stay one step ahead of the law.