Impact of disintegrants on rheological properties and printability in SSE 3D printing of immediate-release formulations.

This study investigates the effects of disintegrants sodium starch glycolate (SSG) and crospovidone (CP) on the printability, rheological properties, and disintegration time of agar and hydroxypropyl methylcellulose (HPMC)-based formulations designed for semi-solid extrusion. Printability was assessed by measuring the dimensional accuracy of manually extruded filaments. Rheological analysis was performed using oscillatory measurements. Principal component analysis (PCA) and Spearman correlation analysis identified three key components (phase angle, critical strain, and elastic modulus) that explained the total variance in the rheological dataset. A 2 x 3 factorial design was employed to evaluate the impact of CP, SSG, and HPMC on these rheological parameters, as well as on printability and disintegration time. Results indicated that formulations containing HPMC and SSG generally exhibited better printability. Formulations containing CP achieved satisfactory printability only when SSG or HPMC was included. The optimal printability and rheological properties were achieved with formulations containing 5 % CP and 10 % SSG. Linear regression models correlated geometric volumes of the model and pycnometric volumes of printed objects, with validation showing that predicted masses were within a 95 % confidence interval of measured values for various shapes. All formulations demonstrated immediate-release properties, confirming the successful fabrication of personalised immediate-release dosage forms using semi-solid extrusion technology.