Topical products physical properties

It is therefore the right time to give a first comprehensive overview of fullerene chemistry, which is the aim of this book. This summary addresses chemists, material scientists and a broad readership in industry and the scientific community. The number of publications in this field meanwhile gains such dimensions that for nonspecialists it is very difficult to obtain a facile access to the topics of interest. In this book, which contains the complete important literature, the reader will find all aspects of fullerene chemistry as well as the properties of fullerene derivatives. After a short description of the discovery of the fullerenes all methods of the production and isolation of the parent fullerenes and endohedrals are discussed in detail (Chapter 1). In this first chapter the mechanism of the fullerene formation, the physical properties, for example the molecular structure, the thermodynamic, electronic and spectroscopic properties as well as solubilities are also summarized. This knowledge is necessary to understand the chemical behavior of the fullerenes. 

The desired physical properties of various topical preparations are listed in Table 12.1. The terms soft and unctuous and hard and stiff are difficult to quantify, hut it is useful at least to consider the variety of descriptions that may be applied in a consistency profile of an external pharmaceutical product. Scheme 12.2 lists these comprehensively, dividing them into primary, secondary and tertiary characteristics. The tertiary properties are prohahly the most elusive. 

The challenges of application techniques are complemented by a consideration of pesticide formulation science. The development of a practical and stable formulation that has the precise chemical and physical properties to enable the delivery of the active ingredient to the site of action is central to this topic. Although the discussion in this book concentrates on the development of products for the application of pesticides to crops via the use of spray application equipment, it recognises that, firstly, the same considerations apply to other areas of application, and that, secondly, formulation science can and does influence the ultimate safety and efficacy of the product. 

A coherent discussion of the above topic should, therefore, include consideration of the relevant aspects of composition, structure, and evolution of the plant cell-walls development of present knowledge concerning the physicochemical properties of cellulosic microfibrils the biological processes that account for the production and properties of the wall materials and the cell organelles that are instrumental in the execution of these processes. The present article provides a brief review of these multidisciplinary subjects. The chemical and physical properties of the structural polysaccharides and their bio-syntheses, have been excellently reviewed in previous Volumes of this Series. Therefore, consideration of these subjects has, so far as possible, been avoided in favor of discussing development of our present knowledge through different approaches and diverse opinions. 

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