Hot-Melt Pneumatic Extrusion-Based 3D-Printed Bilayer Tablets Enabling Sequential Release of Levocetirizine and...

Background/Objectives: This study aimed to develop bilayer tablets using hot-melt pneumatic extrusion (HMPE)-based 3D printing for the integrated treatment of allergic rhinitis and asthma. The formulation combined levocetirizine dihydrochloride (immediate release) and montelukast sodium (delayed release) within a single dosage form to provide a sequential-release formulation strategy relevant to the intended pharmacological roles of the two drugs. Distinct polymer matrices were selected for each drug layer to ensure mechanical robustness, stability, and appropriate release characteristics. Methods: The printed tablets were systematically characterized by mechanical testing, differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and in vitro dissolution. Drug content uniformity was evaluated in accordance with USP <905>. Results: The tablets satisfied USP standards for content uniformity and exhibited sufficient mechanical strength for handling and packaging. DSC and PXRD analyses indicated amorphization of levocetirizine within the polymer matrix, while the amorphous state of the raw montelukast used in this study was retained after printing. In vitro dissolution tests demonstrated immediate release of levocetirizine in acidic medium (pH 1.2) and delayed release of montelukast at intestinal pH (6.8), thereby achieving the intended dual-phase release profile. Conclusions: These findings demonstrate the feasibility of fabricating an HMPE-based 3D-printed bilayer tablet integrating immediate-release levocetirizine and delayed-release montelukast, with reproducible dual-phase release and drug-specific solid-state and performance characteristics within a single oral dosage form.