Preparation and characterization of nanofibrous sheets for enhanced oral dissolution of nebivolol hydrochloride.

Nebivolol-loaded electrospun nanofibrous sheets were prepared for the dissolution enhancement of the active with the aim of improving its oral bioavailability. Physicochemical characterization of nanofibers including differential scanning calorimetry, attenuated total reflectance Fourier transform infrared spectroscopy and positron annihilation lifetime spectroscopy were carried out in order to track the physicochemical changes related to the electrospinning process. The obtained results unanimously indicated the amorphous transition of nebivolol as a result of electrospinning, furthermore supramolecular ordering of chains of polyvinyl alcohol matrix could be revealed by positron annihilation lifetime spectroscopy. The crystalline-amorphous conversion of the active, along with the increased specific surface area of the nanofibers enabled rapid and complete dissolution. More than twice amount of active released from the fibrous sheets than from the commercial tablets. In contrast to the control tablets, the dissolution was complete and was not influenced by the pH of the applied media.