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

The purpose of this work is to evaluate the buccal bioadhesive performance of film.s made by four different chitosan derivatives: chitosan chloride (CL., 13), chitosan glutamate (G.,13), 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 forms and it proved able to discriminate between bioadhesion properties of films made by different chitosans and with different TPP:chitosan molar ratios. All films, with the exception of the MP films, have biphasic bioadhesion profile, showing a bioadhesiveness drop over a fixed amount of TPP which depends on the type of chitosan. This comparative study has enabled G213 and MP to be chosen as the most promising chitosan derivatives aimed at optimizing the designing of controlled drug delivery via buccal bioadhesive films.