Orodispersible films based on blends of trehalose and pullulan for protein delivery

During the last decades the number of therapeutic proteins increased tremendously on the pharmaceutical market. However, due to their often poor stability and limitations of the administration route, the application of therapeutic proteins is a major challenge. The oral mucosa has been suggested as a possible route for protein delivery. In this study, we prepared protein loaded orodispersible films (ODFs), based on blends of trehalose/pullulan by air- and freeze-drying. These two carbohydrates were selected based on the excellent protein stabilizing capacity of trehalose and film-forming ability of pullulan. ODFs were loaded with three model proteins. Ovalbumin was used to study the effect of protein incorporation on the mechanical properties, disintegration time, uniformity of weight and thickness of the ODFs. Lysozyme and beta-galactosidase were used to evaluate protein stability. Ovalbumin loading did not significantly influence the mechanical properties of freeze-dried ODFs, while incorporation of ovalbumin in air-dried ODFs led to a substantial reduction in tensile strength. The trehalose/pullulan ratio had no impact on the stability of lysozyme, while the stability of beta-galactosidase increased with increasing trehalose/pullulan ratios. Furthermore, freeze-drying appeared to be favorable over air drying for process stability while the reverse was found for storage stability. In conclusion, trehalose/pullulan-based ODFs are from a technical point promising for possible protein delivery via the oral cavity.