Functional physico-chemical, ex vivo permeation and cell viability characterization of omeprazole loaded buccal films for paediatric drug delivery

Buccal films were prepared from aqueous and ethanolic Metolose gels using the solvent casting approach (40 °C). The hydration (PBS and simulated saliva), mucoadhesion, physical stability (20 °C, 40 °C), in vitro drug (omeprazole) dissolution (PBS and simulated saliva), ex vivo permeation (pig buccal mucosa) in the presence of simulated saliva, ex vivo bioadhesion and cell viability using MTT of films were investigated. Hydration and mucoadhesion results showed that swelling capacity and adhesion was higher in the presence of PBS than simulated saliva (SS) due to differences in ionic strength. Omeprazole was more stable at 20 °C than 40 °C whilst omeprazole release reached a plateau within 1 h and faster in PBS than in SS. Fitting release data to kinetic models showed that Korsmeyer–Peppas equation best fit the dissolution data. Drug release in PBS was best described by zero order via non-Fickian diffusion but followed super case II transport in SS attributed to drug diffusion and polymer erosion. The amount of omeprazole permeating over 2 h was 275 ug/cm2 whilst the formulations and starting materials showed cell viability values greater than 95%, confirming their safety for potential use in paediatric buccal delivery.