Preparation of electrospun polyurethane nanofiber mats for the release of doxorubicine.

Polyurethane (PU) and doxorubicine loaded-PU nanofiber mats were prepared by the electrospinning technique. The effect of some system and process parameters including flow rate, distance from collector, and concentration of solution on the size and morphology of nanofibers was investigated. The size, morphology and drug content of nanofiber mats were followed by scanning electron microscopy (SEM). FTIR and TGA methods were used for structural and thermal characterization, and DSC was also used for determining the form of drug within nanofiber mat. Doxorubicine release kinetics were studied in two different pHs (4.5 and 7.5) for two drug content and it was observed that there is an inverse correlation between the amounts of drug loaded and released.

Preparation and characterization of some cellulose derivatives nanocomposite films.

One of the most studied biocomponents is cellulose and its derivatives. Chemical structures of the nanocomposite films were investigated by Fourier Transform Infrared Spectroscopy (FT-IR) and X-Ray Diffraction (XRD) analyses. In the Scanning Electron Microscope (SEM) images taken at 5000 x magnification, the films with the best dispersion of nano-reinforcements; are amine modified nano SiO2 doped 2-hydroxyethyl cellulose (2-HEC) and hydroxypropyl cellulose (HPC) films. SiO2 dispersion has not been homogeneous in neutral nano SiO2 doped HPC and hydroxypropyl methylcellulose (HPMC) films. On the other hand, in the amine modified nano SiO2 doped HPMC film, micron-size agglomerations were observed on the film surface. When the thermal resistance of the films was examined, it was determined that the amine modified nano SiO2 doped HPMC film was the highest at 344 °C. When stress-strain values were compared, amine modified nano SiO2 doped HPMC film was the best film sample with a strain value of 101.7 %.

Ofloxacin Loaded Electrospun Fibers for Ocular Drug Delivery: Effect of Formulation Variables on Fiber Morphology and Drug Release.

Ofloxacin (OFL) loaded poly(ε-caprolactone) (PCL) and PCL: poly(butylene succinate) PBS fibers as a drug delivery system in the treatment of ocular infections were prepared by electrospinning. In particular, the effect of some formulation variables including polymer:drug ratio (9:1, 8:2 and 7:3 w/w), solvent systems like dichloromethane (DCM), N,N-dimethylformamide (DMF), N,Ndimethylacetamide (DMAc) and dimethylsulfoxide (DMSO), polymer blends of PCL:PBS at 80:20, 60:40 and 40:60 ratios on fiber morphology, fiber size were investigated. The morphology and diameter of the electrospun fibers were investigated by scanning electron microscopy (SEM) images also the thermal properties were evaluated by differential scanning calorimetry (DSC). The drug release behaviour from fibers and in vitro antibacterial activity were also studied. It was noticed that the average fiber diameter decreased with decreasing polymer amount in initial composition meanwhile the release of drug increased with increasing amount of drug in formulations. Solvent system of DCM:DMF at 80:20 ratio improved fiber morphology and resulted in a reduction in fiber diameter. It was found that smooth surface, flexible fibers with uniform morphology were obtained with 80:20 ratio of PCL:PBS compositions. All fibers showed a burst release of OFL. The initial amount of the released OFL was found to vary as a function of PCL:OFL ratio and polymer composition in the fiber. The microbiological activity of optimized formulation was evaluated using P. aeruginosa, S. epidermidis, S. Aureus and E. coli strains and the results of this study clearly demonstrated that freely released OFL from fibers inhibited the growth of the tested bacteria. The process of electrospinning had no adverse effect on the activity of incorporated drug in fibers.