Daiichi Sankyo Co. will buy Zepharma Inc., Astellas Pharma Inc.'s nonprescription drug unit, for 23.5 billion yen on April 13, Daiichi Sankyo and Astellas said Friday.

Daiichi Sankyo plans to integrate Daiichi Sankyo Healthcare Co., a subsidiary established in December, with Zepharma in April 2007, creating the third-largest drug maker in Japan's nonprescription market in terms of sales, after Taisho Pharmaceutical Co. and Takeda Pharmaceutical Co.

The envisaged firm is expected to have annual sales of more than 50 billion yen.

Zepharma was created in October 2004 through the integration of the nonprescription drug divisions of Yamanouchi Pharmaceutical Co. and Fujisawa Pharmaceutical Co. Yamanouchi and Fujisawa subsequently merged into Astellas last April.

Astellas said it decided to sell Zepharma because the subsidiary, though profitable, is too small to be competitive.

According to industry sources, Astellas entered into negotiations with Taisho earlier this year to try to sell Zepharma.

Astellas later changed its negotiating partner to Daiichi Sankyo as there are few overlaps in the two companies' product lineups and the scale of their operations is about the same, they said.

Zepharma, which markets the popular Gaster 10 stomachache remedy, Cakonal and Precol for colds, and the Makiron disinfectant, chalked up 22.4 billion yen in sales in fiscal 2004.