The tailored manufacturing of core (cellulose acetate)-sheath (polyvinylpyrrolidone) polymeric nanofibers for biphasic drug delivery systems using pressure-spinning

• Manufacturing core-sheath nanofibers from non-pressure spinnable CA combined with PVP using CSPS for the first time. • The diameter and release profile of the pressure-spun fibers tailored by drug loading and spinning parameters. • A combination of hydrophobic CA and hydrophilic PVP creating a fast-slow biphasic release system. • Structural integrity and release stability maintained after 8 weeks of storage. Pressure-spinning is a straightforward method for manufacturing core-sheath fibers with diameters spanning from the submicrometer to micrometer scale. In this study, for the first time, a combination of cellulose acetate (CA)-polyvinylpyrrolidone (PVP) is utilized as a pressure-spun fiber matrix, despite CA having traditionally been regarded as non-pressure-spinnable. The fibers are then loaded with ibuprofen to create a biphasic drug delivery system. The resulting fibers are amorphous and cylindrical with smooth surfaces, with diameters ranging from 370 nm to 1 µm. It is observed that higher ibuprofen concentrations increase fiber diameter, while the application of higher spinning parameters has the opposite effect. In vitro dissolution tests reveal a dual-phase release profile, with an initial burst release due to the hydrophilic PVP sheath, followed by a sustained release phase attributed to the hydrophobic CA core. The release profile can then be tuned through fiber diameter and drug concentration adjustments. Notably, after 8 weeks of storage under ambient conditions, the fibers maintain an amorphous structure and consistent release profiles, showcasing excellent stability. These findings highlight pressure-spinning as a versatile technique for fabricating core-sheath nanofibers with customizable drug release, offering practical advantages for pharmaceutical applications in terms of enhancing therapeutic precision and patient outcomes.