Native and polymeric beta-cyclodextrins in performance improvement of chitosan films aimed for buccal delivery of poorly soluble drugs

b-Cyclodextrin (bCD) and its soluble polymeric derivative (EPIbCD) were used to improve the effectiveness of chitosan-based bucco-adhesive film formulations containing bupivacaine hydrochloride and triclosan as poorly-soluble model drugs. The film formulations were characterized in terms of swelling, mucoadhesion and in vitro drug release, while possible interactions between the components were investigated by DSC and FTIR analyses. For both drugs EPIbCD showed a higher solubilizing efficiency than bCD; however cyclodextrin effectiveness in improving the release rate from film formulations was influenced by their different interactions with chitosan. Free bCD acted as a channelling agent, favouring the film swelling, while EPIbCD due to interaction with chitosan caused an opposite effect. bCD was the optimal partner for bupivacaine-loaded films in terms of film swelling, mucoadhesion and drug release. Contrariwise, EPIbCD was the best partner for triclosan-loaded films, allowing the highest drug release rate increase, due to its higher solubilizing ability with respect to bCD. Addition of the suitable cyclodextrin enabled formulation of buccal films with suitable drug release properties.