Nanoparticle topical applications

Not withstanding the use of nanoparticles for intravenous and topical applications, improvement in oral bioavailability is one of the most important contributions attained through nanotechnology. Molecules that are poorly water soluble may be poorly absorbed because of a lack of sufficient concentrations of solubilized drug. Formulations that are amorphous can overcome this by supersaturation of the dissolution medium allowing for greater absorption of the delivered dose. However, stability problems are significant for... 

Ozbas-Turan, S., Akbuga, J., Sezer, A. D. (2010). Topical application of antisense oligonucleotide-loaded chitosan nanoparticles to rats. Oligonucleotides. 20,147-53. 

Solid lipid nanoparticles have been used for topical application for various dmgs, such as tropolide, imidazole antifungals, anticancers, vitamin A, isotretinoin, ketoconazole, DNA, flurbiprofen, and glucocorticoids (Choi et al., 2006) and also in various formulations of sunscreens and UV blockers (Wissing and Muller, 2001). 

Cui et al. explored the topical application of chitosan-based nanoparticles containing plasmid DNA (pDNA) as a potential approach for genetic immunization... 

Schafer-Korting, M., Mehnert,W. G. Korting, H. C. (2007). Lipid nanoparticles for improved topical application of drugs for skin diseases. Adv. Drug Deliv. Rev., 59, 427-443. 

Gene delivery vehicle Topical application of plasmid-DNA based chitosan nanoparticles... 

It should be understood that the types of toxic effects discussed above are limited to situations where nanoparticles ctfe inhcded or placed in the trachea as insoluble particles. The form of nanoparticles in applications are either dissolved in solution (e.g., through injection for medical uses) or inside components (e.g., computers) and are likely not available for exposure in these ways. We expect that the risk of toxic effects is significantly reduced in these types of products. However, incidental inhalation exposure by workers in the industry represents a potential health issue that requires more research. This is well understood by the U.S. National Institute of Occupational Safety and Health (NIOSH). They recommend limiting exposure to workers until more knowledge is gained, and have identified ten key research topics, including ... 

The definition above is a particularly restrictive description of a nanocrystal, and necessarily limits die focus of diis brief review to studies of nanocrystals which are of relevance to chemical physics. Many nanoparticles, particularly oxides, prepared dirough die sol-gel niediod are not included in diis discussion as dieir internal stmcture is amorjihous and hydrated. Neverdieless, diey are important nanoniaterials several textbooks deal widi dieir syndiesis and properties [4, 5]. The material science community has also contributed to die general area of nanocrystals however, for most of dieir applications it is not necessary to prepare fully isolated nanocrystals widi well defined surface chemistry. A good discussion of die goals and progress can be found in references [6, 7, 8 and 9]. Finally, diere is a rich history in gas-phase chemical physics of die study of clusters and size-dependent evaluations of dieir behaviour. This topic is not addressed here, but covered instead in chapter C1.1, Clusters and nanoscale stmctures, in diis same volume. 

Another advantage cited for organic electronics is their perceived low environmental impact and high expected consumer safety. This assumption is generally based on the notion that plastics are easily recycled and are considered safe to humans and animals. However, the materials used are often completely new compositions with poorly understood health and safety attributes. The assumption that all plastics are completely safe for humans is inaccurate, as is exemplified by recent concerns about the toxicity of polyvinyl chloride (PVC).39 In contrast, most inorganic nanoparticle materials are already on the consumer market and have extensive historical data on their safety in a variety of applications. Some materials, such as zinc oxide, are even considered reasonably safe for ingestion and therefore are commonly used in food and cosmetics. However, the health effects and interactions of nanoparticles on the human body are still a topic of debate.40... 

The lure of new physical phenomena and new patterns of chemical reactivity has driven a tremendous surge in the study of nanoscale materials. This activity spans many areas of chemistry. In the specific field of electrochemistry, much of the activity has focused on several areas (a) electrocatalysis with nanoparticles (NPs) of metals supported on various substrates, for example, fuel-cell catalysts comprising Pt or Ag NPs supported on carbon [1,2], (b) the fundamental electrochemical behavior of NPs of noble metals, for example, quantized double-layer charging of thiol-capped Au NPs [3-5], (c) the electrochemical and photoelectrochemical behavior of semiconductor NPs [4, 6-8], and (d) biosensor applications of nanoparticles [9, 10]. These topics have received much attention, and relatively recent reviews of these areas are cited. Considerably less has been reported on the fundamental electrochemical behavior of electroactive NPs that do not fall within these categories. In particular, work is only beginning in the area of the electrochemistry of discrete, electroactive NPs. That is the topic of this review, which discusses the synthesis, interfacial immobilization and electrochemical behavior of electroactive NPs. The review is not intended to be an exhaustive treatment of the area, but rather to give a flavor of the types of systems that have been examined and the types of phenomena that can influence the electrochemical behavior of electroactive NPs. 

Table 1.1 summarizes the types of processes for generating nanoparticles that are currently involved in the top-down and bottom-up approaches (or their mixed variants). It should be noted that many of these processes have their origin and primary applications predominantly in the pharmaceutical industry so far the commercial food applications of nanotechnology are still in their infancy. For each of the processes mentioned in Table 1.1, the kinds of nanoparticles involved are listed along with a brief indication of their characteristic properties and their approximate particle dimensions. Also presented are some recent literature sources on these various topics (mainly review-type articles) where the interested reader can obtain further background material. 

Coordination compounds have become very usable in medicine [361-364]. In this respect, use of metal complexes (mostly those of lanthanides) as diagnostic [365-367] and anticancer [368-370] media should be specially emphasized. Among the last complexes, the aminoplatinum-containing compounds play an important role, so the structural study of platinum complexes as a model of nucleobases [371] is a topic of renewed interest. The new issue of Comprehensive Coordination Chemistry II [372] contains a wide description of nanoparticles (vols. 6 and 7), biocoordination chemistry (vol. 8), and other aspects of application of coordination compounds. 

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