Evaluation of bioadhesive performance of chitosan derivatives as films for buccal application

The purpose oJ this work is to evaluate the buccal bioadhesive perJormance oJfilms made by Jour different chitosan derivatives: chitosan chloride (CL213), chitosan glutamate (C2l3), 5-methyl-pyrrolidinone chitosan (MP) and a partially reacetylated chitosan (RC). Films were prepared by casting and ionically cross-linked by tripolyphosphate (TPP) using increasing TPP:chitosan molar ratio (20:1-200:1). A rapid and simple in vitro test based on use of buccal cell suspension was modified to assess bioadhesion of solid dosage Jorms and it proved able to discriminate between bioadhesion properties oJfilms made by different chitosans and with different TPP:chitosan molar ratios. Allfilms, with the exception oJ the MP films, have biphasic bioadhesion profile, showing a bioadhesiveness drop over a fixed amount oJ TPP whicli depends on the type oJ chitosan. This comparative study has enabled G213 and MP to be chosen as the most promising chitosan derivatives aimed at optimizing the designing oJ controlled drug delivery via buccal bioadhesive films.