Pharmaceutical giant Merck, which recently completed its $430 million acquisition of Inspire Pharmaceuticals, is closing that company’s Raleigh headquarters Aug. 31 and eliminating 51 jobs. Merck notified North Carolina officials Wednesday of its plans to shut down the headquarters. “The entire facility is to be closed,” Merck wrote in the letter to the N.C. Department of Commerce. Last month, Merck said it planned to close Inspire’s local headquarters before the end of the year. At that time, the company had about 60 workers in Raleigh. Merck bought Inspire to expand its lineup of treatments for eye ailments.