Preparation and in-vitro evaluation of lidocaine hydrochloride oral mucoadhesive films

Abstract

The purpose of this present study was to prepare mucoadhesive film for oral mucosal administration of lidocaine HCl as a viable alternative dosage form to lidocaine HCl injection in dentistry. The mucoadhesive film was prepared using various mucoadhesive polymers, hydroxypropyl methylcellulose (HPMC) of different grades, Methocel E4M and E15, hydroxypropyl cellulose (HPC), sodium carboxymethylcellulose (CMC) and chitosan. Citric acid and menthol were added in formulation to improve the taste of the obtained films. The adhesive properties, tensile properties, morphology, physiochemical properties, and in vitro release and penetration were evaluation. The results showed that the drug loading films of CMC were precipitated. Chitosan provided yellowish films while HPMCs and HPC provided clear films. The obtained films were thin and so flexible to be used along the curvature of the oral cavity. The formulations containing HPMC E15 as mucoadhesive polymer produced films with the highest mucoadhesive strength. The physicochemical characterization revealed the compatibility of ingredients in films and lidocaine HCl existed in the films as molecular dispersed or amorphous form. Increasing the drug to polymer ratios trended to obtain unhomogeneous films. Combination of HPMC E15 and HPC provided rough and porous films. HPMC E4M films were harder and stronger than HPMC E15 films. Chitosan provided hard and brittle films, while HPC provided soft and tough films. Incorporation of HPC into HPMC E15 film was to reduce the rigidity of HPMC E15 film. Eighty percent of drug penetrated from films of HPMCs, HPC and combination of HPMC E15 and HPC through dialysis membrane within 60 minutes while the release of drug from chitosan films was more sustained. The penetrations kinetic of the drug from the obtained films were the best fitted with Weibull model. The drug penetrate from obtained films through dialysis membrane was controlled by the combination of diffusion and polymer chain relaxation mechanisms.