Fig. (3) Combined effect of HPMC and EC on (a)- hardness, (b)- pH, (c)- mucoadhesive time, (d)- in vitro release at 1 h, (e)- in vitro release at 2 h, (f)- in vitro release at 3 h, (g)- in vitro release at 4 h, (h)- in vitro release at 5 h of propranolol HCl buccal tablet.