Direct Powder Extrusion of Atorvastatin 3D-Printed Tablets for Immediate-Release: Solid-State Characterization and Dissolution Performance

Abstract

Thermal extrusion is a well-established approach for producing amorphous solid dispersions (ASDs) to enhance the solubility, dissolution, and bioavailability of poorly water-soluble drugs. Atorvastatin calcium trihydrate (ACT), a BCS class II lipid-lowering agent, exhibits low aqueous solubility, limited oral bioavailability, and variable absorption. The present study investigated the feasibility of fabricating immediate-release ACT tablets using a direct powder extrusion (DPE) three-dimensional (3D) printing technique, thereby enabling in situ drug amorphization and tablet fabrication in a single step. Critical process parameters (CPPs), including nozzle speed, printhead temperature, infill density, and extrusion pressure, were systematically optimized to achieve reproducible oval-shaped tablets with acceptable mechanical integrity and structural fidelity. Among the evaluated polymeric systems for improved dissolution, a combination of 25% (w/w) polyethylene glycol (PEG), 25% (w/w) polyethylene oxide (PEO), 15% (w/w) Pluronic F127, and 15% (w/w) sorbitol yielded consistent DPE printing at a 25% infill density, which has been shown to improve dissolution. The 3D-printed tablets, characterized by physicochemical, structural, and thermal analyses, confirmed successful drug amorphization. In vitro dissolution testing in phosphate buffer (PBS, pH 6.8) demonstrated rapid tablet disintegration and immediate drug release, with ~86% of ACT released within 30 min, meeting United States Pharmacopeia (USP) specifications for immediate-release ACT tablets. Accelerated stability studies (40°C/75% RH) for 3 months showed retention of the amorphous state, as confirmed from DSC and pXRD, with dissolution profiles comparable to initial results. Overall, the findings demonstrated that DPE-based thermal extrusion 3D printing enables single-step fabrication of amorphous ACT tablets with improved dissolution performance and stability, highlighting its potential as a single-step, flexible, patient-centric manufacturing platform at the point of service.

Graphical Abstract