A former employee of Pfizer Japan Inc. has filed a lawsuit with the Tokyo District Court, demanding 1 billion yen in remuneration from the pharmaceutical company for his invention of technology while working for the firm, it was learned Friday.

The suit, filed July 6, says the man invented technology that allows hypertension drug tablets to be divided easily for adjustment of doses when he headed a drug laboratory at Pfizer Japan, the Japanese unit of the U.S. drug maker, in 1993 and 1994.

Pfizer applied for a patent on the technology in 1994 and it was registered in 1999.

The man claims he should have received some 5.4 billion yen out of more than 20 billion yen Pfizer earned from the technology. His suit covers part of the estimated money.

A spokesman for Pfizer Japan said Friday that the company will specify its position in the litigation.

In 2001, the former Pfizer employee filed a different suit with the same court, demanding 70 million yen in remuneration for what he claimed was his invention regarding another patent. But he lost the suit, failing to be recognized as an effective inventor of the technology subject to the patent.