Query: Nanofibers in Drug delivery systems

title: Clay nanoparticles as pharmaceutical carriers in drug delivery systems
abstract: Clay minerals are a class of silicates with chemical inertness, colloid, and thixotropy, which have excellent physicochemical properties, good biocompatibility, low toxicity, and have high application potential in biomedical fields. These inorganic materials have been widely used in pharmaceutical excipients and active substances. In recent years, nanoclay mineral materials have been used as drug vehicles for the delivery of a variety of drugs based on their broad specific surface area, rich porosity, diverse morphology, good adsorption performance, and high ion exchange capacity. Areas covered This review introduces the structures, properties, and applications of various common natural and synthetic nanoclay materials as drug carriers. Natural nanoclays have different morphologies including nanoplates, nanotubes, and nanofibers. Synthetic materials have controllable sizes and flexible structures, where mesoporous silica nanoparticles, laponite, and imogolite are typical ones. These inorganic nanoparticles are often linked to polymers to form multifunctional drug delivery systems for better pharmaceutical performance. Expert opinion The clay nanomaterials have typical properties, including enhanced solubility of insoluble drugs, targeting therapeutic sites, controlled release, and stimulation of responsive drug delivery systems.

title: Review of the fabrication techniques and applications of polymeric electrospun nanofibers for drug delivery systems
abstract: Drug delivery systems (DDSs) are a promising avenue for targeted drug delivery over a given time frame. Different techniques have been devised for drug encapsulation in a delivery system which can carry it to the target site and release it as a function of time. The biochemical properties of encapsulation systems are tailored according to the required release profile for the target tissue. Electrospun fibers have been greatly investigated recently for the development of DDSs. Different applications for specific fiber types have been fabricated and tested in order to determine their clinical significance. This review critically analyzes the potential applications of electrospun fibers in drug delivery system (DDS)

title: Current Applications of Biopolymer based Scaffolds and Nanofibers as Drug Delivery Systems
abstract: The high surface to volume ratio of polymeric nanofibers makes them an effective vehicle for the release of bioactive molecules and compounds such as growth factors, drugs, herbal extracts and gene sequences. Synthetic polymers are commonly used as sensors, reinforcements and energy storage, whereas natural polymers are more prone to mimicking an extracellular matrix. Natural polymers are a renewable resource and classified as an environmentally friendly material, which might be used in different techniques to produce nanofibers for biomedical applications such as tissue engineering, implantable medical devices, antimicrobial barriers and wound dressings, among others. This review sheds some light on the advantages of natural over synthetic polymeric materials for nanofiber production. Also, the most important techniques employed to produce natural nanofibers are presented. Moreover, some pieces of evidence regarding toxicology and cell interactions using natural nanofibers are discussed. Clearly, the potential extrapolation of such laboratory results into human health application should be addressed cautiously.

title: Current applications of biopolymer based nanofibers as drug delivery systems and scaffolds.
abstract: Polymeric nanofibers possess a high surface to volume ratio, which makes them an effective vehicle for the release of bioactive molecules and compounds such as growth factors, drugs, herbal extracts and gene sequences. Synthetic polymers are commonly used for sensors, reinforcements and energy storage, whereas natural polymers are more prone to mimicking an extracellular matrix. Natural polymers have a renewable resource and are classified as an environment friendly material, which might be used in different techniques to produce nanofibers for biomedical applications such as tissue engineering, implantable medical devices and antimicrobial barriers and wound dressings, among others. This review sheds some light on the advantages of natural over synthetic polymeric materials for nanofiber production. Also, the most important techniques used to produce the natural nanofibers are presented. Moreover, some evidences regarding toxicology and cell interactions using natural nanofibers are discussed. It seems clear that much care needs to be taken in order to potentially extrapolate the results obtained in a laboratory level into human health application.

title: Electrospun sandwich configuration nanofibers as transparent membranes for skin care drug delivery systems
abstract: The development of biocompatible nanocomposites for biomedical applications such as drug release has attracted increasing attention in recent years. In this work, electrospun membranes composed of polycaprolactone (PCL) and shellac were fabricated because PCL has favorable mechanical and biological properties, such as high biocompatibility and biodegradability. Meanwhile, shellac is biocompatible and non toxic; as a result, the fabricated membranes are attractive for controlled drug delivery. Here, PCL/shellac/PCL nanofiber membranes were treated by ethanol vapor to improve their properties for use in drug delivery applications. Salicylic acid was loaded in the drug delivery system as a model drug, and three PCL/shellac/PCL membrane configurations were investigated. Ethanol vapor treatment increased the tensile strength, flexibility, and transparency of the membranes. Both the tensile strength and drug release properties of the membranes strongly depended on the ratio of PCL to shellac.

title: Development of Novel Doxorubicin Loaded Biodegradable Polymeric Nanofibers as the Anticancer Drug Delivery Systems
abstract: Through the present research, for the first time, doxorubicin hydrochloride (DOX) loaded poly (e caprolactone) poly (ethylene glycol) poly (e caprolactone) (PCL PEG PCL, PCEC) nanofibers were obtained by blending electrospinning method. The physicochemical characteristics of the DOX/PCEC nanofibers were fully evaluated. Nanofibers had homogeneous morphology with mean diameters ranging from 80 to 300 nm. The drug releasing behavior showed the faster release rate by increasing the drug content in nanofibers. The in vitro release profile and release kinetics from the DOX/PCEC nanofibers confirmed that the release profile followed Korsmeyer Peppas model suggesting a Fickian diffusion as a major drug release mechanism.

title: Electrospun gelatin/sodium bicarbonate and poly(lactide co e caprolactone)/sodium bicarbonate nanofibers as drug delivery systems.
abstract: In this work, we report electrospun nanofibers made of model hydrophobic (poly(lactide co e caprolactone) PLCL) and hydrophilic (gelatin) polymers. We explored the effect on drug release of the incorporation of sodium bicarbonate (SB) into these fibers, using the potent antibacterial agent ciprofloxacin as a model drug. The fibers prepared are smooth and have relatively uniform diameters lying between ca. 600 and 850nm. The presence of ciprofloxacin in the fibers was confirmed using IR spectroscopy. X ray diffraction showed the drug to be incorporated into the fibers in the amorphous form. In vitro drug release studies revealed that, as expected, more rapid drug release was seen with gelatin fibers than those made of PLCL, and a greater final release percentage was obtained. The inclusion of SB in the gelatin fibers imparts them with pH sensitivity: gelatin/SB fibers showed faster release at pH5 than pH7.4, while fibers without SB gave the same release profiles at both pHs. The PLCL fibers have no pH sensitivity, even when SB was included, as a result of their hydrophobic structure precluding the ingress of solvent. In vitro cell culture studies showed that all the fibers are able to promote cell proliferation. The ciprofloxacin loaded fibers are effective in inhibiting Escherichia coli and Staphylococcus aureus growth in antibacterial tests. Thus, the gelatin based fibers can be used as pH responsive drug delivery systems, with potential applications for instance in the treatment of tumor resection sites. Should these become infected, the pH would drop, resulting in ciprofloxacin being released and the infection halted.

title: Multiscale modeling of nanoengineered drug delivery systems based on smart nanofibers
abstract: N smart drug delivery systems becoming one the most promising directions in the development of modern therapies which could dramatically improve drugs efficiency through targeted/precise delivery. However, despite the progress made during last years, there still remains an enormous potential for further development which could revolutionize the area. Unfortunately, in some cases, this potential is screened out by the complexity and multilevel character of systems and processes at the nanoscale. The success of future applications in high tech medicine requires a deep understanding of fundamental mechanisms at different levels of description and their communication. That could be provided only by an appropriate combination of experimental study with predictive theoretical modeling. This study addresses the multiscale modeling of drug release (on/off states) in the smart nanofiber based drug delivery systems to better understand the process and factors defining the mechanism, which could be efficiently used to deliver drugs. The properties (as well as the ratio) of monomers and temperature are becoming important variables that affect the drug release. So first, the constituent monomers and small copolymers were studied by quantum chemical methods. Next, the number of different copolymer systems was constructed and the molecular dynamics calculations were performed in water solvent with ions. The resulting trajectories were analyzed in detail (structure of radial distribution functions, a number of hydrogen bonds, etc. to study the crosslinking between polymers. The MD calculations were also supported by statistical mechanical studies (3D RISM) to get the solvation properties and thermodynamics of the equilibrium arrangements. Finally, the detailed structure of favorite relative orientations of copolymers was studied by quantum chemical methods to understand the factors affecting drug release process.

title: Nanofibers Fabricated Using Triaxial Electrospinning as Zero Order Drug Delivery Systems.
abstract: A new strategy for creating functional trilayer nanofibers through triaxial electrospinning is demonstrated. Ethyl cellulose (EC) was used as the filament forming matrix in the outer, middle, and inner working solutions and was combined with varied contents of the model active ingredient ketoprofen (KET) in the three fluids. Triaxial electrospinning was successfully carried out to generate medicated nanofibers. The resultant nanofibers had diameters of 0.74 0.06 mm, linear morphologies, smooth surfaces, and clear trilayer nanostructures. The KET concentration in each layer gradually increased from the outer to the inner layer. In vitro dissolution tests demonstrated that the nanofibers could provide linear release of KET over 20 h. The protocol reported in this study thus provides a facile approach to creating functional nanofibers with sophisticated structural features.

title: Electrospun Poly(N isopropylacrylamide)/Ethyl Cellulose Nanofibers as Thermoresponsive Drug Delivery Systems.
abstract: Fibers of poly(N isopropylacrylamide) (PNIPAAm) ethyl cellulose (EC) and a blend of both were successfully fabricated by electrospinning. Analogous drug loaded fibers were prepared loaded with ketoprofen (KET) Scanning and transmission electron microscopy showed that the fibers were largely smooth and cylindrical, with no phase separation observed. The addition of KET to the spinning solutions did not affect the morphology of resultant fibers, and no drug particles could be observed to separate from the polymer matrix. X ray diffraction demonstrated that the drug was present in the amorphous physical form in the fiber matrix. There are significant intermolecular interactions between KET and polymers, as evidenced by IR spectroscopy and molecular modeling. Water contact angle measurements proved that the PNIPAAm and PNIPAAm/EC fibers switched from being hydrophilic to hydrophobic when the temperature was increased through the lower critical solution temperature of 32degC. In vitro drug release studies found that the PNIPAAm/EC blend nanofibers were able to synergistically combine the properties of the 2 polymers, giving temperature sensitive systems with sustained release properties. In addition, they were established to be nontoxic and suitable for cell growth. This study demonstrates that electrospun blend PNIPAAm/EC fibers comprise effective and biocompatible materials for drug delivery systems and tissue engineering.