Bioadhesive polymeric film-based integrative platform for the unidirectional carbamazepine release from a volatile microemulsion

Abstract Carbamazepine (CBZ) shows inconsistent absorption primarily due to its poor dissolution rate. In this study, we describe a bioadhesive polymeric film, embedded with microemulsion (ME), as a tool to enable improved CBZ dissolution and achieve sustained release. The ME was formulated using pseudo-ternary components; water, oil (n-butyl acetate), surfactant (tocopheryl polyethylene glycol 1000 succinate, TPGS) and cosurfactant (1,4-butanediol). The region at surfactant to co-surfactant ratio of 1:1 was characterized using dynamic light scattering, small angle neutron scattering and differential scanning calorimetry. Scattering studies showed that size distribution did not change upon water addition and temperature. Optimized ME composition containing CBZ was embedded into bioadhesive films composed with a backing layer. We successfully demonstrate the confinement of CBZ-ME into the film matrix and thereupon, the achievement of unidirectional sustained drug release up to 8 h. Our further investigations are directed over testing the system for localized drug delivery applications.