Design and evaluation of the two-layer mucoadhesive film of phentolamine mesylate to reverse oral soft tissue local anesthesia

Long soft tissue anesthesia in dentistry results in problems such as difficulties in speaking and swallowing، inadvertent biting of soft tissues and a temporary negative influence on patients’ quality of life. Intra-oral injection of phentolamine mesylate is used to decrease local anesthesia duration. Mucoadhesive film containing phentolamine mesylate can be used as a needle-free form of drug to reduce tissue damage and local pain. The aim of this study was to design and evaluate a two-layer film of phentolamine mesylate with one layer containing drug and the other containing a resistant layer for diffusion of the drug in one direction. In this experimental study، mucoadhesive polymers and drug were used in the first layer and ethyl cellulose was used in the second layer. Disintegrating agents، osmotic agents and plasticizers were used in first layer. The prepared films were evaluated in terms of physical and pharmaceutical properties including flexibility، thickness، ex vivo adhesion، disintegration time، superficial pH، and drug content and in vitro drug release. The formulation was selected based on standards of previous studies. Of 44 different formulations the mucoadhesive film prepared by mixing PVA and NaCMC polymers and sodium starch glycolate disintegrating agent was desirable in terms of pharmaceutical features and had the highest drug release rate (96%). EC100cps polymer and alcohol as a solvent were selected in order to prepare the second layer. In order to reverse soft tissue local anesthesia in dentistry، producing of phentolamine mesylate mucoadhesive film is possible with suitable pharmaceutical effects.