A drugstore selling Viagra in Hangzhou, Zhejiang province. Pfizer is about to lose its Chinese patent for sildenafil, sold as Viagra, and Chinese drug companies will be given the opportunity to capture the erectile dysfunction medication market. Hu Jianhuan / For China Daily

Chinese drug companies have been given the opportunity to capture the erectile dysfunction medication market as Pfizer Inc is about to lose its Chinese patent for sildenafi citratel, sold as Viagra.

The US pharmaceutical giant's exclusive right to sell Viagra in China expires in July.

Meanwhile, Chinese companies' generic equivalents are now in the approval pipeline, and hope to get the production green light soon.

One such drugmaker, Guangzhou Baiyunshan Pharmaceutical Co Ltd, is readying its own version of the blue pill for a production license.

"We are not sure whether our ED drug will generate much profit, but we know it is a huge market," Chen Jing, Baiyunshan board secretary, told Shanghai Securities News.

The profits of the new product should reach up to 1 billion yuan ($162.5 million), a person familiar with the company said.

Since sildenafil is one of Pfizer's major products in the Chinese market, experts said its business performance in China will be affected. Two foreign ED drugmakers, Eli Lilly and Co and Bayer AG, also will be put on notice.

"Booming Chinese drugmakers will promote their versions of the ED product at a much lower price, less than half than that of sildenafil," said Guo Wei an analyst with Ipsos, a global market research company.

Sildenafil reportedly accounted for about 60 percent of the Chinese market for ED drugs in 2013, compared with a 20 percent share for the Eli Lilly's Cialis and 10 percent for the Bayer drug for ED, Levitra.

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