Pre-formulation Study of 3D-Printed Topical Film by Semisolid Extrusion Incorporated with Spray-dried Extract of <i>Punica granatum</i> Linn

OBJECTIVE: Linn. leaves and determine how formulation properties and infill architecture influence film performance. SIGNIFICANCE: Three-dimensional printing is a promising platform for individualized topical dosage forms with controlled geometry and composition. However, successful incorporation of herbal active ingredients into semisolid printable matrices requires appropriate preformulation to ensure printability, structural fidelity, and preservation of bioactive compounds after processing. METHOD: leaf SDE and biopolymers were screened using physicochemical, mechanical, and printability-related parameters, including collapse factor, printing angle, and printability. Films were then produced by SSE 3D printing with cubic or grid infill and characterized for tensile behavior, disintegration time, and total polyphenol recovery. RESULTS: Preformulation screening enabled selection of inks suitable for SSE printing and successful production of structured topical films containing the herbal extract. Infill architecture significantly influenced film performance. Grid-patterned films showed greater rupture force (4.98 ± 0.66 N) and longer disintegration time (25.54 min) than cubic-patterned films (3.54 ± 0.55 N and 22.58 min, respectively), indicating greater mechanical resistance and slower matrix disruption. In contrast, cubic-patterned films showed higher total polyphenol recovery (34.491 vs. 27.037 g pyrogallol equivalents). CONCLUSION: leaf SDE. The results demonstrate that both preformulation attributes and infill design influence key preliminary performance parameters, including structural integrity, disintegration, mechanical behavior, and polyphenol recovery. These findings support the use of internal architecture as a formulation tool to modulate film properties; however, further adhesion, release, permeation/retention, and dose uniformity studies are required to confirm the suitability of the system for topical application.