Development and Physicochemical Characterization of Fast-Dissolving PVA/Poly(ε-caprolactone) Modified with Succinic Acid Films for Oral Drug Delivery

This study aims to develop biodegradable, gelatin-free polymer films using polyvinyl alcohol (PVA) and succinic acid–modified poly(ε-caprolactone) (PCS). The objective is to assess their structural compatibility, mechanical performance, and disintegration behaviour, with a view toward their application as oral capsule materials. PVA/PCS films containing 20–80% PCS were fabricated via solvent casting. Structural characteristics were investigated using FTIR and XRD, while AFM, SEM, and EDX provided insights into surface morphology and elemental composition. Tensile testing evaluated mechanical properties, and disintegration studies were carried out in simulated gastric fluid. Additionally, molecular docking was used to analyse polymer–polymer interactions, and in silico ADME predictions were performed to assess biocompatibility and oral suitability. Results from FTIR and XRD confirmed hydrogen bonding interactions and a reduction in crystallinity with increasing PCS content. Morphological analysis showed smooth and homogeneous surfaces at low PCS levels, while higher PCS concentrations led to phase separation. EDX confirmed consistent elemental profiles. The incorporation of PCS reduced tensile strength and modulus yet preserved high flexibility. Notably, films with 80% PCS disintegrated within 7 min in gastric conditions, whereas pure PVA films remained intact. Molecular docking (ΔG = –0.9 kcal/mol; Ki = 4.6 µM) indicated favourable interactions between components, and ADME analysis confirmed good absorption and compliance with Lipinski's Rule of Five. These findings demonstrate that PVA/PCS films are promising biodegradable and gelatin-free alternatives to conventional capsules, offering a balance of structural stability, rapid disintegration, and biocompatibility for effective oral drug delivery.