Preparation and characterization of nanofibers containing amorphous drug dispersions generated by electrostatic spinning

Purpose. We assessed the application of water-soluble polymer-based nanofibers prepared by electrostatic spinning as a means of altering the dissolution rate of the poorly water-soluble drug, itraconazole. Methods. Organic solvent-based solutions of itraconazole/HPMC mixtures were electrostatically spun at 16 and 24 kV. The formed nanofibers were collected as a non-woven fabric. The samples were analyzed by scanning electron microscopy, differential scanning calorimetry, and dissolution rate. Results. Scanning electron microscopy showed fiber diameters of 1-4 mum and 300-500 nm depending on the applied voltage. Differential scanning calorimetry measurements found that the melting endotherm for itraconazole was not present, suggesting the formation of an amorphous solid dispersion or solution. Dissolution studies assessed several presentations including direct addition of the non-woven fabrics to the dissolution vessels, folding weighed samples of the materials into hard gelatin capsules and placing folded material into a sinker. Controls included a physical mixture as well as solvent cast and melt extruded samples. Electrospun samples dissolved completely over time with the rate of dissolution depending on the formulation presentation and drug to polymer ratio. The physical mixture did not appreciably dissolve in these conditions. Conclusions. The application of electrostatic spinning to pharmaceutical applications resulted in dosage forms with useful and controllable dissolution properties.