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Objectives: Polyurethanes (PUs) are a popular choice for composing nanofibers due to their spinnability, biocompatibility, high chemical stability, and good mechanical and elasticity properties. The desired release behaviors are also achieved by using combinations of PUs and various polymers. In this study, we investigated effects of polyvinylpyrrolidone (PVP) and ethyl cellulose (EC) on PU electrospun nanofibers in terms of morphological structures and drug release characteristics. Materials and Methods: Nanofibers were prepared using blends of PU with either EC or PVP in different ratios by electrospinning. The effects of PVP or EC on the morphology and diameter of the prepared nanofibers were examined with scanning electron microscope (SEM). The compatibility of the components used in the formulations of nanofibers was determined by attenuated total reflection (ATR)-fourier-transform infrared (FTIR). Donepezil hydrochloride (DNP), a water soluble compound, was selected as a model drug to examine its release characteristics from both PU/PVP and PU/EC electrospun nanofibers. In vitro drug release studies from electrospun nanofibers were performed according to the method defined in the monograph as the "paddle over disk method" of United States Pharmacopeia 38. Results: The SEM images showed that addition of EC or PVP to PU solutions did not affect the generation of nanofibers, and those formed had a smooth surface without beads in nanoscale. The ATR-FTIR spectra disclosed that EC and PVP were separately incorporated into the PU matrix. The in vitro release data indicated that the presence of EC or PVP in PU nanofibers dramatically changed the release behavior of DNP. PU/EC nanofibers (F4) provided sustained drug release with the Korsmeyer-Peppas drug release kinetic mechanism, in which the release rate was controlled by diffusion of the drug, while all of the PU/PVP nanofibers exhibited fast drug release. Conclusion: Overall, these characteristics of PU/EC (10/8) electrospun nanofibers has suggested their potential use as a drug carrier from which water-soluble drug release may occur in a sustained fashion. [ABSTRACT FROM AUTHOR]

Objectives: Azithromycin dihydrate is a macrolide antibiotic used for the treatment of several types of bacterial infections. The drug shows low oral bioavailability due to its low solubility. In the present work solid lipid nanoparticles of azithromycin dihydrate were formulated, keeping in view enhancement of the solubility and rate of dissolution of the drug. Materials and Methods: Azithromycin dihydrate loaded stearic acid nanoparticles were formulated by high shear homogenization using three different surfactants, namely Tween 20, poloxamer 188, and poloxamer 407, at a varied lipid surfactant ratio while keeping the quantities of the active ingredient constant. Twelve such formulations were prepared. The nanoparticles obtained were evaluated for drug content, % drug loading, % entrapment efficiency, particle size analysis, zeta potential, surface morphology, Fourier transmission infrared spectroscopy, in vitro drug release, and stability. Results: All the formulations showed good entrapment efficiency and high percentage of in vitro release with a particle size suitable for lymphatic absorption. The nanoparticles formulated with poloxamer 188 showed better characteristics compared to the other surfactants. Conclusion: This study indicates that stearic acid nanoparticles of azithromycin dihydrate prepared by high shear homogenization can be successively used for improvement of dissolution and thereby oral bioavailability of the drug. [ABSTRACT FROM AUTHOR]