Otsuka Pharmaceutical Co., Ltd. , abbreviated OPC, is a pharmaceutical company headquartered in Tokyo, Osaka and Naruto, Japan. The company was established August 10, 1964.

Naruto is a city located in Tokushima Prefecture, Japan. As of 30 June 2022, the city had an estimated population of 54,989 in 26,206 households and a population density of 410 persons per km2. The total area of the city is 191.11 square kilometres (73.79 sq mi).