A Randomized, Two-Treatments, Two-Periods, Crossover, Open label, Laboratory-Blind, Single Dose Bioequivalence Study between Vildagliptin/Metformin 50 mg/1000 mg Film Coated Tablets (Sensityn(R)) and Galvusmet(R)50 mg/1000 mg Film Coated Tablets in healthy adults under fed conditions