An electrospun fiber of polyvinyl(pyrrolidone) (PVP)-Tween 20 (T20) with curcumin as the encapsulated drug has been developed. A study of intermolecular interactions was performed using Raman spectroscopy, Fourier transform infrared (FT-IR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD).The Raman and FT-IR studies showed that curcumin preferrably interacted with T20 and altered PVP chain packing, as supported by XRD and physical stability data. The hydroxyl stretching band in PVP shifted to a lower wavenumber with higher intenstity in the presence of curcumin and PVP, indicating that hydrogen bond formation is more intense in a curcumin or curcumin-T20 containing fiber. The thermal pattern of the fiber did not indicate phase separation. The conversion of curcumin into an amorphous state was confirmed by XRD analysis. An in vitro release study in phosphate buffer pH 6.8 showed that intermolecular interactions between each material influenced the drug release rate. However, low porosity was found to limit the hydrogen bond-mediated release.Key words curcumin; fiber; electrospinning; interaction; porosity; polymeric drug delivery system Curcumin is the major constituent of turmeric rhizome (Curcuma sp.).1) Curcumin has a number of demonstrated pharmacological effects, such as antioxidant, anti-inflammatory, anticancer, hepatoprotective, 1) antimicrobial, and antiviral. 2)Clinical trials have proven that curcumin is well tolerated by the body, with a maximum dose of 12 g daily.3) Unfortunately, the efficacy of curcumin is limited by its poor solubility in water, as well as its instability under light, heat, and alkaline conditions.1) The solubility of curcumin in aqueous buffer (pH 5) is reported to be 11 ng/mL.3) Moreover, the absorption of curcumin in the gastrointestinal tract is very low, leading to poor bioavailability (in animals and humans).2) Therefore, designing an effective delivery system is necessary in order to address the limitations of curcumin use. 1-3)A wide range of drug delivery systems has been developed to improve the bioavailability of poorly soluble drugs, including fast-dissolving tablets, 4) incorporation into a hydrophilic complex, 1) micellization, and solid dispersion. 5) Electrospinning, a technique of producing thin strands of fiber using high voltage, has opened up opportunities in the development of drug delivery systems. An optimized electrospinning process can produce nano-sized fibers. 6)The high surface area and porosity of these electrospun fibers are advantageous in their use as carriers for poorly water-soluble drugs.5) The high surface area generally increases the dissolution rate of the incorporated drug, thus potentially enhancing its bioavailability. 5)Therefore, the incorporation of curcumin into an electrospun fiber is expected to improve its oral bioavailability.Tailoring a suitable drug-loaded fiber requires careful selection of materials, in addition to an optimized production process and environment. Generally, the drug is mixed with a polymer s...

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Backgroundα-Mangostin is a major active compound of mangosteen (Garcinia mangostana L.) pericarp extract (MPE) that has potent antioxidant activity. Unfortunately, its poor aqueous solubility limits its therapeutic application. Purpose: This paper reports a promising approach to improve the clinical use of this substance through electrospinning technique.MethodsPolyvinylpyrrolidone (PVP) was explored as a hydrophilic matrix to carry α-mangostin in MPE. Physicochemical properties of MPE:PVP nanofibers with various extract-to-polymer ratios were studied, including morphology, size, crystallinity, chemical interaction, and thermal behavior. Antioxidant activity and the release of α-mangostin, as the chemical marker of MPE, from the resulting fibers were investigated.ResultsIt was obtained that the MPE:PVP nanofiber mats were flat, bead-free, and in a size range of 387–586 nm. Peak shifts in Fourier-transform infrared spectra of PVP in the presence of MPE suggested hydrogen bond formation between MPE and PVP. The differential scanning calorimetric study revealed a noticeable endothermic event at 119°C in MPE:PVP nanofibers, indicating vaporization of moisture residue. This confirmed hygroscopic property of PVP. The absence of crystalline peaks of MPE at 2θ of 5.99°, 11.62°, and 13.01° in the X-ray diffraction patterns of electrospun MPE:PVP nanofibers showed amorphization of MPE by PVP after being electrospun. The radical scavenging activity of MPE:PVP nanofibers exhibited lower IC50 value (55–67 µg/mL) in comparison with pure MPE (69 µg/mL). The PVP:MPE nanofibers tremendously increased the antioxidant activity of α-mangostin as well as its release rate. Applying high voltage in electrospinning process did not destroy the chemical structure of α-mangostin as indicated by retained in vitro antioxidant activity. The release rate of α-mangostin significantly increased from 35% to over 90% in 60 minutes. The release of α-mangostin from MPE:PVP nanofibers was dependent on α-mangostin concentration and particle size, as confirmed by the first-order kinetic model as well as the Hixson–Crowell kinetic model.ConclusionWe successfully synthesized MPE:PVP nanofiber mats with enhanced antioxidant activity and release rate, which can potentially improve the therapeutic effects offered by MPE.

Indium tin oxide (ITO) nanofibers were successfully prepared via an electrospinning method, followed by annealing at 400 °C. Mixed solutions of ITO nanoparticle sol and polyethylene oxide (PEO) were used as precursors of the nanofibers. The PEO decomposed during annealing to yield ITO fibers. The fibers were characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD), thermo-gravimetric/differential thermal analysis (TG/DTA), UV-vis spectrophotometry and four-probe resistivity measurements. The diameter of the prepared fibers was controlled by adjusting the flow rate and the applied electric current. In(2)O(3) crystallized in the ITO nanofibers with a crystallite size of 27 nm. The optical transmittance in the visible region approached 90% in films deposited for 5 min, confirming that the nanofiber film is still transparent in the optical region. The sheet resistance of the nanofiber film was linearly dependent on the inverse of the deposition time and on the PEO/ITO ratio.