"April 23, 2007 – The FDA today approved the first generic versions of Ambien (zolpidem tartrate) immediate-release tablets. The following 13 manufacturers have received FDA approval for zolpidem tartrate tablets: Mylan Pharmaceuticals, TEVA Pharmaceuticals USA, Roxane Laboratories, Watson Laboratories, Ranbaxy Laboratories, Dr. Reddy’s Laboratories, Apotex, Synthon Pharmaceuticals, Genpharm, Mutual Pharmaceutical Company, Caraco Pharmaceutical Laboratories, Carlsbad Technology, and Lek Pharmaceuticals."
https://www.webmd.com/sleep-disorders/news/20070423/fda-oks-generic-ambien