Self-inflating floating nanofiber membranes for controlled drug delivery.

Floating gastro-retentive delivery systems can prolong the gastric residence providing sustained drug release. In this study, we report on self-inflating effervescence-based electrospun nanofiber membranes embedding polyethylene oxide/sodium bicarbonate cast films. In this system, sodium bicarbonate results in an effervescence effect by creating carbon dioxide gas upon contacting an acidic gastric fluid, with the resulting gas bubbles being entrapped within the swollen network of nanofibers. Eudragit RL and RS polymers are utilized as a host material to manipulate release kinetics of incorporated drugs. Pramipexole, a common medication for chronic Parkinson's disease (PD), is used as a model drug. Uniform and bead-free nanofibers with diameters of ~300 nm were obtained. Although floating nanofibers initially exhibited high water contact angles (WCA), water droplets were quickly absorbed into the surface and the WCA decreased to ~0° within 60 s. Floating lag time, total floating time, swelling properties and drug release profiles were investigated both in a simulated gastric fluid (pH 1.2 buffer solution) and in a simulated intestinal fluid (pH 6.8 buffer solution) at 37 °C. All floating nanofiber formulations began to float instantly with nearly zero floating lag time and did not sink into the solution even after 24 h. By comparison, the same formulations without sodium bicarbonate cast films could not maintain continuous floating beyond 15 min. The floating nanofiber pouches presented lower initial release of between 20 and 57 %, compared to that of non-floating nanofiber pouches (40-82% within 2 h). Clearly, floating nanofibers reduced the initial burst release and provided sustained drug release. This demonstrates the potential to result in 'once-a-day' oral introduction of drugs that normally must be taken frequently. Effervescence-based floating nanofibers present a novel and promising prototype delivery system for the drug delivery in the upper gastro-intestinal (GI) tract.