Controllable and Switchable Ibuprofen Release from Temperature Responsive Polymers

Electrospun polymeric nanofibers have found many practical applications in medical and pharmaceutical sciences. Currently, it is still challenging to obtain drug delivery systems that can deliver drug molecules at switchable rates with minimum burst effect. In this study, three types of nanofibers (NFs) made up of a combination of Poly(ε-caprolactone) (PCL), poly(N-isopropylacrylamide) (pNIPAM), and ibuprofen (IP) were fabricated using an electrospinning method to study their drug diffusion behaviours. It was found that pNIPAM had a quasilinear drug diffusion at temperatures above its lower critical solution temperature (LCST), 32˚C, but had a serious burst effect at room temperature. On the other hand drug diffusion rates from PCL NFs could not be varied by temperature (22-34˚C). In order to correct for the burst effect experienced by the pNIPAM NFs, a core-shell structure fiber made of a PCL shell and pNIPAM core was proposed. The PCL would serve to provide a layer of protection for the core fiber, thus enabling the IP to maintain a steady diffusion in the first hours. We also tried to introduce an efficient infrared absorber, carbon nanotubes, into the core, purposing to switch on/off the IP diffusion by using infrared stimulus. Such a controllable drug delivery system could likely be of application in pharmaceutical and biomedical sciences, especially programmable transdermal drug delivery