Amphastar Pharmaceuticals, Inc. engages in the development, manufacture, market, and sale of technically challenging and proprietary injectable, inhalation, and intranasal products. It operates through Finished Pharmaceutical Products and Active Pharmaceutical Ingredients Products segments. The Finished Pharmaceutical Products segment manufactures, markets, and distributes Primatene Mist, enoxaparin, naloxone, phytonadione, lidocaine, and other critical and non-critical care drugs. The Active Pharmaceutical Ingredients Products segment manufactures and distributes recombinant human insulin and porcine insulin. The company was founded by Zi-Ping Luo and Yong Feng Zhang on February 29, 1996 and is headquartered in Rancho Cucamonga, CA.