Carbon nanotubes: applications in pharmacy and medicine.

Carbon nanotubes (CNTs) are allotropes of carbon, made of graphite and constructed in cylindrical tubes with nanometer in diameter and several millimeters in length. Their impressive structural, mechanical, and electronic properties are due to their small size and mass, their strong mechanical potency, and their high electrical and thermal conductivity. CNTs have been successfully applied in pharmacy and medicine due to their high surface area that is capable of adsorbing or conjugating with a wide variety of therapeutic and diagnostic agents (drugs, genes, vaccines, antibodies, biosensors, etc.). They have been first proven to be an excellent vehicle for drug delivery directly into cells without metabolism by the body. Then other applications of CNTs have been extensively performed not only for drug and gene therapies but also for tissue regeneration, biosensor diagnosis, enantiomer separation of chiral drugs, extraction and analysis of drugs and pollutants. Moreover, CNTs have been recently revealed as a promising antioxidant. This minireview focuses the applications of CNTs in all fields of pharmacy and medicine from therapeutics to analysis and diagnosis as cited above. It also examines the pharmacokinetics, metabolism and toxicity of different forms of CNTs and discusses the perspectives, the advantages and the obstacles of this promising bionanotechnology in the future.

Development of novel amphiphilic magnetic molecularly imprinted polymers compatible with biological fluids for solid phase extraction and physicochemical behavior study.

In the present work, a novel amphiphilic magnetic molecularly imprinted polymer (M-MIP) has been synthesized by a simple non covalent method for the loading of gatifloxacin (GTFX) in polar solvent. This nanomaterial used as sorbent has been applied to the solid phase extraction of GTFX in different spiked biological fluids. For the first time, studies of dispersibility and solubility behaviors with different solvents and water were performed to demonstrate amphiphilicity and also to find the better nanomaterial obtained. Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray (XRD) were used to characterize the nanomaterials, and Scatchard plot analysis to demonstrate the binding kinetic. Results suggest that the dispersibility, solubility and the adsorption in water have relationships with the structure of nanomaterials prepared. The oleic acid coated on the M-MIP combined with the washing process has enhanced the amphiphilicity of the nanomaterials. The M-MIP2 showed better selectivity and adsorption behavior with imprinted efficiency higher than (2) in water, as well as in biological fluids. Moreover, no interference with constituents of blank urine and blank serum samples for solid phase extraction (SPE) was observed. Moreover, loading recovery was found higher than 95% with low RSD. The novel amphiphilic magnetic nanomaterial prepared here as sorbent is suitable for SPE of GTFX in biological fluids for therapeutic monitoring control. It could be also used as carrier in drug delivery system for experimental and clinical studies.

Anticancer loading and controlled release of novel water-compatible magnetic nanomaterials as drug delivery agents, coupled to a computational modeling approach.

The preparation, characterization and application of novel anticancer "epirubicin" (EPI) water-compatible magnetic molecularly imprinted polymers (M-MIPs) like artificial antibodies by computational design and chemical synthesis as a carrier for drug delivery is described herein. Two monomers: methacrylic acid (MAA) and methacrylamide (MAM) were selected by computational simulation from the four chemicals used. Covalent and non-covalent bonds were evaluated by this technique based on the interaction mode and energy with template or solvent. Non-covalent bonding was predominant in all cases and major energy interaction was observed. The nanomaterials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), and a vibrating sample magnetometer (VSM). The loading and controlled release studies performed showed a slight advantage for the M-MIP obtained from MAA than that from MAM at ambient temperature. However, the drug release in vitro was slightly better for the second M-MIP when the temperature increased to 50 °C. The water-compatible nanomaterial showed good pH-sensitive drug release profiles in vitro. Briefly, due to its magnetic property, amphiphilicity, good biomimetic recognition of EPI, high adsorption capacity and controlled release, the epirubicin M-MIPs synthesized in this study are suitable to be applied to a magnetic targeted drug delivery system.

Adsorption behavior of pazufloxacin mesilate on amino-functionalized carbon nanotubes.

In this study, the interaction between amino-functionalized multi-walled carbon nanotubes (e-MWNTs) and antibacterial agents was investigated and the drug-loading ability of e-MWNTs was evaluated. The e-MWNTs were prepared and characterized, then were used as adsorbents for loading an antibacterial agent, pazufloxacin mesilate (PZFX). The adsorption behavior of PZFX on e-MWNTs in water was investigated. The results showed that e-MWNTs were able to form supramolecular complexes with PZFX and could be used as drug carriers with high drug-loading efficiency. Compared with pristine multi-walled carbon nanotubes (MWNTs), the adsorption efficiency of e-MWNTs was better. In kinetic studies, the pseudo-second-order model showed satisfactory fitting and good adsorption process. Langmuir model was successfully employed to describe the adsorption isotherms of PZFX on e-MWNTs and higher drug-loading ability were observed from e-MWNTs with smaller diameter. The adsorption process of e-MWNTs was sensitive to the pH and it was observed that the neutral pH gave the best adsorption. Low temperatures facilitated the adsorption process. In addition, the release process of PZFX from e-MWNTs occurred in two stages: a rapid release, then followed by a slow release, in which acidic solution favored the release process. In summary, our technique developed for the adsorption of PZFX on e-MWNTs is satisfactory.

Free radicals, antioxidants in disease and health.

Free radicals and oxidants play a dual role as both toxic and beneficial compounds, since they can be either harmful or helpful to the body. They are produced either from normal cell metabolisms in situ or from external sources (pollution, cigarette smoke, radiation, medication). When an overload of free radicals cannot gradually be destroyed, their accumulation in the body generates a phenomenon called oxidative stress. This process plays a major part in the development of chronic and degenerative illness such as cancer, autoimmune disorders, aging, cataract, rheumatoid arthritis, cardiovascular and neurodegenerative diseases. The human body has several mechanisms to counteract oxidative stress by producing antioxidants, which are either naturally produced in situ, or externally supplied through foods and/or supplements. This mini-review deals with the taxonomy, the mechanisms of formation and catabolism of the free radicals, it examines their beneficial and deleterious effects on cellular activities, it highlights the potential role of the antioxidants in preventing and repairing damages caused by oxidative stress, and it discusses the antioxidant supplementation in health maintenance.