A drug-trafficking ring allegedly responsible for producing an estimated 3 billion Taiwan dollars (103 million US dollars) of illegal drugs over four years was busted, dpa quoted Taiwan\'s Coast Guard as saying Thursday. Investigators made the bust after a one-year sting operation in central Taiwan. The ring involved drug manufacturers distributing non-branded cold medicine to more than 50 local pharmacies, which in turn sold the medicine to illegal drugmakers. The drugmakers, using four underground factories, refined the cold medicine into ephedrine and amphetamines, two addictive stimulants, and shipped the drugs mostly to China, the coast guard said. Authorities arrested 11 people Wednesday who were accused of involvement in refining the drugs. They are now expanding the probe to the cold medicine\'s original manufacturers. \'This is the first time we\'ve ever collected enough evidence to implicate the whole chain,\' said Chen Tso-ling, the coast guard task force chief who led the bust. \'We will be making more arrests in the next two days.\' In February, Taiwan authorities made the largest one-time drug bust in 10 years, stopping a shipment of amphetamines and ketamine worth 500 million Taiwan dollars at Taoyuan Airport.