Nevertheless, the European Commission has developed a number of initiatives with emphasis on safety and ethical considerations but also to evaluate the appropriateness

of existing methodologies to assess the potential risks associated with nanotechnology. In this context, it is mentioned that there is still insufficient knowledge and data concerning nanoparticles characterization, their detection and measurement, the persistence of nanoparticles in humans and the environment, and all aspects of toxicology related to these particles to allow satisfactory risk assessments. In order to deal with this issue, the EMEA has created the Innovative Task Force for the coordination of scientific and regulatory Inhibitors,research,lifescience,medical ARRY-162 nmr competence. Because novel applications of nanotechnology will span the regulatory boundaries between medicinal products and medical Inhibitors,research,lifescience,medical devices, the mechanism of action will be the key to decide whether a product should be regulated as a medical product or a medical device. Furthermore, evaluation of the quality, safety,

efficacy, and risk management must be discussed in more detail. In conclusion, it is likely that the evaluation of such new products will require special considerations. Therefore, EMA will promote this process either to develop specific Inhibitors,research,lifescience,medical guidelines or for the update of existing once. 2. Preparation Techniques 2.1. General Introduction into Techniques Lipid molecules have to be introduced into an aqueous environment for the preparation of

liposomes independent of liposome size and structure. A general overview representing Inhibitors,research,lifescience,medical the correlation of the way of lipid hydration, respectively, the way of primary liposome formation with the resulting liposome structure, was originally developed by Lasic [38]. Several ways of treating the lipids are known to support the hydration of these molecules, as lipid molecules themselves are poorly soluble in aqueous compartments. These procedures can be categorized as shown in Table 2. Table 2 Methods of liposome preparation and the resulting product. Partly from Lasic and Barenholz [39]. Additional methods have Inhibitors,research,lifescience,medical been developed such as freeze thawing, freeze drying, and extrusion. Neuron – Cell However, they are all based on preformed vesicles. In the following sections, liposome preparation techniques are described with respect to the principle of lipid hydration/liposome formation as well as process design and description. In addition, the advantages and disadvantages of each technique are pointed out. Furthermore, focus is given on discussing the techniques with respect to their applicability regarding large-scale production for clinical purposes and good manufacturing practice (GMP) relevant issues. 3. Mechanical Methods 3.1. Preparation by Film Methods Properties of lipid formulations can vary depending on the composition (cationic, anionic, and neutral lipid species).