Controlled release of Doxycycline from gum acacia/poly(sodium acrylate) microparticles for oral drug delivery

Electrospun polymer fibers modified with FK506 for the long-term treatment of acute cardiac allograft rejection in a heart transplantation model

FK506, a first-line immunosuppressant, is routinely administered orally and intravenously following heart transplantation. However, frequent administration can result in a substantial psychological burden to patients, resulting in non-adherence to medication. The purpose of our study is to overcome the disadvantages of systemic drug administration by developing a polymer-based delivery system that is tunable and biodegradable and that can release highly hydrophobic FK506 over extended periods to treat or prevent acute cardiac allograft rejection. Using an electrospinning method, long-acting microfibers were prepared, and FK506 appeared to be continuously released for up to 14 days based on the in vitro release profiles. After implanting the microfiber subcutaneously into the abdominals of transplanted rats, it was found that the infiltration of T cells and macrophages and the secretion of interleukin-2 (IL-2) and IL-1β were significantly reduced compared with those of the free FK506 groups. More importantly, the mean survival time (MST) of the PCL-FK506 group was significantly extended in comparison with that of untreated control recipients and free FK506 (MST of untreated control recipients, free FK506, and PCL-FK506 was 8, 26.1, and 37, respectively). In conclusion, we propose that this drug delivery approach would be suitable for developing long-lasting immunomodulatory agents that prolong cardiac graft survival safely and effectively.

Multistimuli-Responsive PNIPAM-Based Double Cross-Linked Conductive Hydrogel with Self-Recovery Ability for Ionic Skin and Smart Sensor

Multistimuli-responsive conductive hydrogels have been appealing candidates for multifunctional ionic skin. However, the fabrication of the multistimuli-responsive conductive hydrogels with satisfactory mechanical property to meet the practical applications is still a great challenge. In this study, a novel poly(N-isopropylacrylamide-co-sodium acrylate)/alginate/hectorite clay Laponite XLS (PNIPAM-SA/ALG/XLS) double cross-linked hydrogel with excellent mechanical property, self-recovery ability, temperature/pH-responsive ability, and strain/temperature-sensitive conductivity was fabricated. The PNSAX hydrogel possessed a moderate tensile strength of 290 kPa at a large elongation rate of 1120% and an excellent compression strength of 2.72 MPa at 90%. The hydrogel also possessed excellent mechanical repeatability and self-recovery ability. Thus, the hydrogel could withstand repetitive deformations for long time periods. Additionally, the hydrogel could change its transparency and volume once at a temperature of 44 °C and change its volume at different pHs. Thus, the visual temperature/pH-responsive ability allowed the hydrogel to qualitatively harvest environmental information. Moreover, the hydrogel possessed an excellent conductivity of 0.43 S/m, and the hydrogel could transform large/subtle deformation and temperature information into electrical signal change. Thus, the ultrafast strain/temperature-sensitive conductivity allowed the hydrogel to quantitatively detect large/small-scale human motions as well as environmental temperature. A cytotoxicity test confirmed the good cytocompatibility. Taken together, the hydrogel was suitable for human motion detecting and environmental information harvesting for long time periods. Therefore, the hydrogel has a great application potential as a multifunctional ionic skin and smart sensor.

On-line dissolution analysis of multiple drugs encapsulated in electrospun nanofibers

Electrospun nanofiber is a very attractive material which can be used as the support to form multiple-drug dosage. Understanding the dissolution process of different active drug ingredients released from electrospun fibers is of great importance to control and evaluate the quality of medicated nanofibers. Here we present the first study of on-line automatic analysis of dissolution of multiple drugs in electrospun fiber mats. Single-needle electrospinning technology is utilized to combine polymers, hydrophilic polyvinylpyrrolidone (PVP) and hydrophobic polycaprolactone (PCL) as carrier to load three poorly water-soluble non-steroidal anti-inflammatory drugs (paracetamol, nimesulide, and ibuprofen). The loading of the drugs in PVP/PCL electrospun fibers are characterized by various techniques, including scanning electron microscopy, X-ray diffraction, Fourier infrared spectroscopy and differential scanning calorimetry. The in vitro dissolution is investigated by our home-made portable analyzer, which can simultaneously on-line determine multiple drugs released from the nanofibers by a single step. The analysis shows a wide linear detection range of the drugs with limit-of-detection (LOD) down to μg/mL-level. The dissolution profiles of three ingredients in nanofibers can be monitored every thirty seconds from the beginning to the end in the entire dissolution process from only one HSCE run. The kinetic information of the dissolution, including the dissolution curve, characteristic dissolution time and dissolution efficiency, is obtained and evaluated for different dissolution media, drug loading content and the ratio of PVP/PCL. Our study provides a promising method for rapid and accurate dissolution testing of nanofiber-based drugs, and would extend the applications of separation techniques in pharmaceutical analysis.

Microwave assisted fast fabrication of zinc/iron oxides based polymeric nanocomposites and evaluation on equine fibroblasts

We aimed to provide a tissue repair material, which can be synthesized rapidly, using polymers mimicking the natural environment in the extra-cellular matrix and metals/minerals. The components should have the potential to be used in tissue repair and simultaneously, reducing the side-effects of the incorporated molecules. It is challenging to manage the dispersibility of ZnO NPs in common solutions like water. Here, we report a novel method for preparing highly dispersible suspensions of ZnO NPs. In contrast to those synthesized by conventional methods, microwave assisted method allowed synthesis of dispersible ZnO NPs and the incorporation of zinc/Iron oxides NPs within alginate and gum matrix (AG) in a short span of time providing high yield of the product. The nanoformulations were characterized for size, morphology, interaction of various chemicals used during their synthesis by transmissible electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and energy dispersive X ray Spectrum. It was also evaluated for cytotoxicity and their effect on equine fibroblast cells. Microwave-assisted fabrication of zinc/iron oxides nanoparticles provided flowerlike morphology with good dispersibility and high yield in a short span of time. Our results revealed that ZnO NPs were more cytotoxic than AG ZnO NPs and doped AG Fe₃O₄ doped ZnO NPs at higher concentrations. Further metal nanoparticles capped with alginate/acacia with size range less than 100 nm demonstrated high stability, good biocompatibility, re-epithelization and enhanced mineralization in horse fibroblast cells.

Doxycycline drug delivery using hydrogels of O-carboxymethyl chitosan conjugated with caffeic acid and its composite with polyacrylamide synthesized by electron beam irradiation

Two hydrogels of O-carboxymethyl chitosan conjugated with caffeic acid and its composite with polyacrylamide were synthesized using electron beam irradiation. The synthesized hydrogels were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and mechanical properties studies. The hydrogels were loaded with doxycycline by swelling and its release was investigated in various media. The effect of the dose of electron beam irradiation and PAAm amount on the properties of hydrogels including swelling, drug loading, drug release, mechanical properties, and gel content were studied. The release of doxycycline form hydrogels in different media obeyed the mechanism of non-Fickian diffusion and best fitted to the Higuchi model and Korsmeyer-Peppas. In-vitro doxycycline release consideration indicated that the drug's release from composite hydrogel occurs with higher amounts than the other one. The cytotoxic study confirmed the non-toxicity of the prepared hydrogels dressing. Moreover, the growth inhibition of permissive bacteria against Staphylococcus aureus and Escherichia coli were observed for doxycycline-loaded hydrogels. So, the synthesized hydrogels are appropriate for practical application as a new antibacterial wound dressing.

Fabrication of doxycycline-loaded electrospun PCL/PEO membranes for a potential drug delivery system

Potential usage of biodegradable and biocompatible polymeric nanofibers is the most attention grabbing topic for the drug delivery system. In order to fabricate ultrafine fibers, electrospinning, one of the well-known techniques, has been extensively studied in the literature. In the present study, the objective is to achieve the optimum blend of hydrophobic and hydrophilic polymers to be used as a drug delivery vehicle and also to obtain the optimum amount of doxycycline (DOXH) to reach the optimum release. In this case, the biodegradable and biocompatible synthetic polymers, poly(ε-caprolactone) (PCL) and poly(ethylene oxide) (PEO), were blended with different ratios for the production of DOXH-loaded electrospun PCL/PEO membranes using electrospinning technique, which is a novel attempt. The fabricated membranes were subsequently characterized to optimize the blending ratio of polymers by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD) and water contact angle analysis. After the characterization studies, different amounts of DOXH were loaded to the optimized blend of PCL and PEO to investigate the release of DOXH from the membrane used as a drug delivery vehicle. In vitro drug release studies were performed, and in vitro drug release kinetics were assessed to confirm the usage of these nanofiber materials as efficient drug delivery vehicles. The results indicated that 3.5% DOXH-loaded (75:25 w/w) PCL/PEO is the most acceptable membrane to provide prolonged release rather than immediate release of DOXH.