Improved pharmaceutical solid oral film dosage forms for the buccal and/or sublingual delivery of pharmaceutical, nutraceutical or cosmetic ingredients are endowed with instant hydration potential and complete dissolution potentially enabling the active ingredient to become immediately available for enhanced buccal and/or sublingual absorption and/or reduced absorption through the gastrointestinal route. The improved delivery systems for solubilizing and stabilizing pharmaceutically active ingredients exhibit enhanced stability by the use of a combination of crystallization inhibitors, which together can maintain the active ingredient in a desired plurality of particles in an effective size range within a polymeric film matrix.