A small Texas pharmaceutical company that is building a sales and marketing headquarters in Blue Bell has won Food and Drug Administration approval for a first-of-a-kind treatment for Attention Deficit Hyperactivity Disorder in patients 6 years and older. Neos Therapeutics Inc. secured final FDA approval late Wednesday for Adzenys, the first oral tablet for ADHD that dissolves in the mouth in less than 30 seconds, and does not require swallowing a pill or capsule.