The Impact of the Core-Shell Fiber Composition on the Properties and Stability of the Electrospun Films

This study aimed to develop and evaluate core-shell electrospun orodispersible films (ODFs) containing lopinavir (LPV) and ritonavir (RTV) for pediatric HIV therapy. The investigation focused on the impact of fiber composition and storage conditions on film morphology, physicochemical stability, mechanical properties, disintegration time, and drug dissolution profiles.

Core-shell ODFs were prepared via co-axial electrospinning using LPV and RTV solutions in Eudragit^® E100 and Kollidon^® VA64 matrices, respectively. Two configurations were tested, ie LPV in the core and RTV in the shell (LPV/RTV), and vice versa (RTV/LPV). Films were characterized using SEM, DSC, XRD, mechanical testing, disintegration and dissolution studies, and uniformity of content analysis. Stability was assessed under long-term (25 °C/60% RH) and accelerated (40 °C/75% RH) conditions over six months.

LPV/RTV films were more homogeneous in their morphology and showed superior stability during storage compared to RTV/LPV films. SEM analysis revealed compact, well-aligned fibers in LPV/RTV mats, while RTV/LPV mats showed heterogeneous, ribbon-like structures. LPV/RTV films disintegrated within 100 ± 37s, meeting requirements of very fast disintegration, whereas RTV/LPV films remained intact for 180 s. Compared to RTV/LPV films, LPV/RTV films showed greater uniformity in API content and stability over time, while both formulations exhibited slight, non-significant shifts in LPV/RTV ratios during storage. Dissolution profiles indicated enhanced release from RTV/LPV films, though structural degradation limited their stability. After storage, for both types of films, partial recrystallization of API was observed. The LPV/RTV films maintained their dissolution performance, whereas the RTV/LPV films showed significant deterioration.

Core-shell electrospun ODFs with LPV in the core and RTV in the shell demonstrated more homogeneous and resistant to storage-related changes, although the release of the active ingredients was characterized by slower dissolution. These findings support the potential of co-axial electrospinning for developing pediatric-friendly antiretroviral formulations.