Physicomechanical characterization and tablet compression of theophylline nanofibrous mats prepared by conventional and ultrasound enhanced electrospinning

Abstract

Theophylline (TEO) nanofibers with polyethylene oxide (PEO) were prepared by conventional electrospinning (ES) and novel needleless ultrasound-enhanced electrospinning (USES). They were compared for Young's modulus, elongation at rupture and rupture stress, tabletability and drug release. Placebo (PEO) or drug-loaded (PEO/TEO 90:10) nanofibers were examined by scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC) and infrared spectroscopy (ATR-FTIR). Nanofibers prepared by USES were thinner than ES nanofibers and drug-loaded nanofibers thinner than placebo. Drug was mostly amorphous and interacted weakly with PEO. Mats generated by USES and also drug-loaded mats demonstrated higher Young's modulus (stiffness) and higher rupture stress. Under compression, USES and drug-loaded nanofibers demonstrated greater compaction work, higher yield pressure (Heckel and K-L models), and produced stronger tablets than ES and placebo respectively. Principal Component Analysis revealed two significant components explaining 91.05% of the variance. The first comprised the compaction work, yield pressure (ductility) and Young's modulus that were positively intercorrelated and elongation at rupture that was correlated negatively. The second comprised the mat rupture stress and tablet breaking load. Drug release from nanofibrous tablets was faster than tablets of physical mixture but there was no difference between the tablets of the two electrospinning methods.