An investigation of the drug release kinetics of 3D-Printed two compartment Theophylline and Prednisolone tablets

Pharmaceutical 3D printing (3DP) not only offers the possibility of dose personalization but also the co-administration of multiple active pharmaceutical ingredients (APIs) in one combination tablet. In this study, Theophylline (TPH) and Prednisolone (PSL) were printed as bi-tablets, which are single tablets with two distinct separate compartments. New findings show that the combination therapy of TPH with systemic corticosteroids shows a highly synergistic effect in the treatment of pulmonary diseases. For TPH, a drug with a narrow therapeutic window (NTW), precise sustained release requirements are mandatory, while PSL requires immediate drug release and is individually administered in doses specifically tied to the treatment progression. The study aims to understand the extent to which the combination of two tablet compartments influences the individual drug dissolution kinetics of the respective single compartments. Utilizing a full factorial statistical experimental design, various practically relevant doses were produced, investigated for their drug release, analyzed using different mathematical model fits, and compared with respective mono-tablets. The results show that the sustained drug release of TPH is not significantly influenced by the addition of a second compartment in relationship to respective doses. Individualization of bi-tablet doses while maintaining similar release profiles is possible with the given design setup, as release curves still show high similarity. In all tablet designs, PSL release occurred sufficiently fast, with the release rate correlating to the surface area-to-volume ratio (SA/V) as the main determining parameter.