Development of Prolonged-Release Orodispersible Minitablets Containing Bisoprolol Fumarate

Background/Objectives: Bisoprolol fumarate (BF) is a cardioselective beta-blocker used to treat pediatric heart failure and certain tachyarrhythmias. Currently, it is administered mainly as extemporaneously prepared suspensions from crushed tablets, which may cause issues with dose accuracy, stability, and palatability. Orodispersible minitablets (MODTs) may facilitate administration and individualized dosing, while prolonged release could potentially reduce peak-to-trough fluctuations and, thus, minimize adverse effects such as hypotension or bradycardia. This proof-of-concept study aimed to develop spray-dried prolonged-release microparticles containing BF, incorporate them into MODTs, and evaluate the effect of compression on drug release. Methods: Microparticles were prepared by spray drying ethanolic solutions of BF and ethylcellulose at 40 °C, 50 °C, and 60 °C. Their characterization included scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis and dissolution studies. Selected microparticles were compressed into 3 mm MODTs, which were evaluated for mechanical properties, disintegration, and BF release. Results: Formulations containing 10% BF and 90% ethylcellulose released from 52.6% to 73% of BF after 2 h, increasing to 84.8–90.0% after 8 h and reaching 96% after 24 h. Solid-state analyses indicated complete amorphization of the drug in these microparticles. The spray-drying temperature affected process efficiency but did not significantly impacted morphology or dissolution behavior. The optimized MODTs disintegrated in less than 30 s and had a tensile strength of up to 2.62 MPa. Importantly, compression increased the initial BF release from 26.4% for the microparticles to 43.9% for the MODTs at 0.5 h, resulting in f2 values of 45.04–48.46. Despite the higher initial BF release, the moderately prolonged-release profile was maintained in the case of MODTs. Conclusions: These findings demonstrate the feasibility of combining prolonged-release microparticles with orodispersible minitablets as a proof-of-concept for a pediatric drug delivery approach.