Electrospun nanofibers as a potential controlled-release solid dispersion system for poorly water-soluble drugs

Abstract

Electrospinning was introduced as a novel technique for preparing controlled-release (CR) amorphous solid dispersions (SD) and polymeric nanofibers of a poorly water-soluble drug. Piroxicam (PRX) was used as a low-dose poorly-soluble drug and hydroxypropyl methylcellulose (HPMC) as an amorphous-state stabilising carrier polymer in nanofibers. Raman spectroscopy, X-ray powder diffraction (XPRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were used in the physical characterisation of the CR–SD nanofibers. Special attention was paid on the effects of a polymer and solvent system on the solid-state properties and physical stability of nanofibers. The average dry diameter of the electrospun CR–SD nanofibers ranged from 400 to 600nm (SEM). PRX existed in amorphous form in the nanofibers immediately after fabrication and after a short-term (3-month) aging at low temperature (6–8°C/0% RH) and ambient room temperature (22°C/0% RH). At higher temperature and humidity (30°C/85% RH), however, amorphous PRX in the nanofibers tended to slowly recrystallise to PRX form III. The electrospun CR–SD nanofibers exhibited a short lag-time, the absence of initial burst release and zero-order linear CR dissolution kinetics. In conclusion, electrospinning can be used to fabricate supersaturating CR–SD nanofibers of PRX and HPMC, and to stabilise the amorphous state of PRX.