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Designing Smart Nanotherapeutics
Published in Suresh C. Pillai, Yvonne Lang, Toxicity of Nanomaterials, 2019
A. Joseph Nathanael, Tae Hwan Oh, Vignesh Kumaravel
MNPs (e.g., iron oxide) have been widely employed for different bio-medical applications (such as drug delivery, medical imaging, and biosensor) under the guidance of an external magnetic field. The US Food and Drug Administration has accepted iron oxide nanoparticles (e.g., Fe3O4) for its clinical use as a magnetic resonance contrast agent (Kim et al. 2011). The magnetism and functionality of the nanoparticles are influenced by their shape, size, particle size distribution, and surface characteristics (Lee et al. 2015). Hydrothermal (Chen et al. 2008), precipitation (Rajamohan et al. 2017, Vignesh et al. 2014), thermal decomposition (Unni et al. 2017), and electro-chemical (Starowicz et al. 2011) methods are commonly used to synthesize MNPs. The biocompatibility and colloidal stability of MNPs are significantly determined by the nature of surface ligands. The surface of Fe3O4 is generally decorated by a polymer with required surface ligands for drug delivery. The surface modification is performed using ligand exchange (e.g., sulfonates, phosphonates, thiols, catechol, and carboxylic acids) and encapsulation (e.g., polymers, silica, DNA, and inorganic metal/metal oxide) techniques. Stimuli-responsive (internal and external) ligands have received much attention in recent years to improve the drug delivery of MNPs (Kang et al. 2017). The interaction of stimuli-responsive MNPs with internal/external factors results in a wide range of structural changes as shown in Figure 6.3a (Kang et al. 2017).
Imaging of Cell Trafficking and Cell Tissue Homing
Published in George C. Kagadis, Nancy L. Ford, Dimitrios N. Karnabatidis, George K. Loudos, Handbook of Small Animal Imaging, 2018
Iron oxide nanoparticles for magnetic resonance imaging contain iron and, although it is a natural and essential mineral, an overdose can be toxic to cells (Soenen et al. 2011). Moreover, aggregation of these nanoparticles in the presence of a magnetic field can lead to embolization (Gupta et al. 2007). Several studies have looked into the adverse effects of iron oxide particles on cells, but the reports have been contradictory. Importantly, however, the variety of the applied methods and model systems to assess cytotoxicity plays a critical role and can contribute significantly to these contradictory findings (Soenen and De Cuyper 2010). As a result, many highlighted the need for a more standardized procedure for the assessment of nanoparticle cytotoxicity. In general, the toxicity associated with iron oxide nanoparticles, or their coatings, appears to be closely related to the release of ions and the generation of free radicals following passage through the cell’s lysosomes (Soenen and De Cuyper 2010; Taylor et al. 2012). On the positive side, the uptake and toxicity of these nanoparticles can be manipulated by modifications in the surface chemistry and selecting the right size and biocompatible coating of the nanomaterial (Alkilany and Murphy 2010).
An Introduction to Two-Piece Hard Capsules and Their Marketing Benefits
Published in Larry L. Augsburger, Stephen W. Hoag, Pharmaceutical Dosage Forms, 2017
The term globally acceptable generally refers to the regions of the United States, the European Union, and Japan. For a global presentation, the available palette of colorants is vastly reduced and mainly consists of the iron oxides, titanium dioxide, and blue #2. It is important to note that blue #2 is a light-sensitive dye that is prone to fading; therefore, light protective packaging should be used to avoid capsule discoloration. Iron oxides present a special challenge as they contain elemental iron, which can be toxic at elevated levels. This is an especially important consideration since the iron oxides are one of the few classes of globally acceptable coloring agents. For reasons of patient safety, guidelines have been established for the daily intake of iron oxides and elemental iron. For example, the World Health Organization has established a limit of 0.5 mg/day/kg of iron oxide, while the US Code of Federal Regulations has an established limit of 5 mg/day of elemental iron. It is therefore incumbent on the formulator to be aware of the levels of iron oxide in their capsule color formulation. This information enables the back calculation of elemental iron levels per capsule; the maximum theoretical intake of elemental iron can be calculated based on the number of capsules to be dosed daily. A reputable capsule supplier can provide assistance in this matter and reformulate to lower iron oxide levels if necessary.
Metal Nanoparticles in Infection and Immunity
Published in Immunological Investigations, 2020
Other metals which have been investigated as nanoparticles, include those composed of copper, iron, and zinc. In addition, semi-metals such as gallium and bismuth have been incorporated into nanoparticles as well (Hernandez-Delgadillo et al. 2013; Vega-Jimenez et al. 2017). Iron and zinc may decompose into the ionic forms of those elements in acidic cellular compartments, and therefore might be considered partially biodegradable. In addition to pure metal, metal oxides feature prominently in the field of nanoparticles, such as iron oxide NPs, zinc oxide (ZnO) NPs, titanium oxide (TiO2) NPs, and others. Iron oxide can be in the form of Fe2O3 (ferric iron, Fe III) or Fe3O4 (Fe II/III). The latter is magnetic, which means it can be used to separate a target from background in vitro or in vivo. Fe3O4 nanoparticles can also be injected into a target tissue (such as cancerous tumor) and then heated by application of a high frequency alternating magnetic field, known as magnetic hyperthermia.
Current trends in chemical modifications of magnetic nanoparticles for targeted drug delivery in cancer chemotherapy
Published in Drug Metabolism Reviews, 2020
Ahmad Gholami, Seyyed Mojtaba Mousavi, Seyyed Alireza Hashemi, Younes Ghasemi, Wei-Hung Chiang, Najmeh Parvin
In another research, magnetite nanoparticles like iron oxide with core/shell structure are primarily used as sources of magnetic materials (Drbohlavova et al. 2009; Ebrahimi et al. 2016). Iron oxide has several crystalline polymorphs called Fe2O3 hematite, Fe2O3 maghemite, Fe3O4 magnetite, and a few other forms (high-pressure forms and amorphous) (Zboril et al. 2002). Nevertheless, only maghemite and magnetite are found to be the most significant interest in bioapplications. Until now, widely MNPs synthesis methods have been investigated. There are many favorable methods to get MNPs by high stability, monodisperse nanoparticles, and shape-controlling (Chen et al. 2018). There are used several methods in the synthesis of MNPs such as coprecipitation (Hashemi et al. 2019), thermal decomposition, microemulsion, sol–gel, and additional chemical processes that are shown in Figure 1 (Avval et al. 2019).
Toxicity evaluation of magnetic iron oxide nanoparticles reveals neuronal loss in chicken embryo
Published in Drug and Chemical Toxicology, 2019
Shweta Patel, Sarmita Jana, Rajlakshmi Chetty, Sonal Thakore, Man Singh, Ranjitsinh Devkar
Commercial use of nanometal oxides in biomedical applications is stemmed due to their bioavailability, enhanced absorption, and their ability to cross biological barriers (Das et al.2009, Wang et al.2010). Although numerous studies focused on investigating their biomedical applications have highlighted versatile nature of nanometal oxides, their toxicity continues to be a major concern (Curwin and Bertke 2011, Brenner et al.2015). Hence, new investigations focused at setting benchmarks for toxicity of nanometal oxides are of pivotal interest and cannot be ignored. Magnetic nanoparticles are reported for their penetrability into human tissues and applications in magnetic resonance imaging (Pankhurst et al.2003, Jae-Hyun et al.2007). Iron oxide nanoparticles (IONs) have been elaborately studied for their targeted drug delivery. Superparamagnetic IONs such as maghemite (γ-Fe2O3) and magnetite (Fe3O4) are known to generate reactive oxygen species (ROS)-mediated toxicity and peroxidation of membrane lipids (Stohs and Bagchi 1995, Singh et al.2012).