OSAKA -- Nihon Schering K.K., a Japanese unit of the major German pharmaceutical group Schering AG, said Thursday that it has absorbed its subsidiary, Mitsui Pharmaceuticals Inc., to improve efficiency.

Nihon Schering, based in Osaka, acquired the Tokyo-based Mitsui Pharmaceuticals last March from Mitsui Chemicals Inc. and made it a wholly owned subsidiary.

Nihon Schering said the move is to streamline areas of duplication between itself and the subsidiary and improve efficiency.

The move is also to expand its business from the mainstay field of manufacturing medical imaging drugs for such equipment as computer tomography to manufacturing drugs for illnesses of the circulatory system, the company said.

Nihon Schering reported sales of 51.6 billion yen in the year that ended in December 1999, while Mitsui Pharmaceuticals logged sales of 15.2 billion yen in the year that ended in March 2000.