development of cross-linked chitosan films for oral mucosal delivery of lidocaine

lidocaine (lc) is a local anesthetic agent. the aim of this study was to prolong the anesthetic effect of this drug in the oral cavity in the treatment of oral mucositis. films of lc were prepared with three different molecular weights (mw) of chitosan in three different concentrations (1-3%) and were then cross-linked by solvent casting evaporation method with tripolyphosphate penta sodium salt (tpp) in two concentrations (0.1 and 0.3%). cross-linking time was 5 min and the solvent was evaporated by oven at 37 ºc. bioadhesion, tensile strength (ts), the release and flux of drug through the films were studied. increasing the concentration of chitosan caused decreasing the bioadhesion while increasing its mw did not change the bioadhesion significantly. the bioadhesion of cross-linked films was comparable to similar films. cross-linking the films with tpp and increasing the chitosan mw significantly increased their ts compared to films obtained from the gels. drug release profiles showed that increasing the concentration and mw of chitosan caused an increase in both the rate and extent of drug release. lidocaine flux was increased by mw and concentration of chitosan but increasing tpp concentration significantly decreased it. films prepared by 3% of high mw of chitosan and cross-linked by 0.1% of tpp (h3t1) showed a higher flux of drug (212.59 ± 26.31 mg/cm2/hr), and relative high bioadhesion and ts. this film is expected to prolong release of lc in buccal area and is suggested for further clinical studies to evaluate its produced onset and duration of anesthesia.