Books
Almost Human?
Intelligent Software for Chemical Analysis Lutgarde M. C. Buydens and Peter J. Schoenmakers, Eds. Elsevier Science Publishers 655 Ave. of the Americas New York, NY 10010
1993, 347 pp., $200 As they state in the preface, the authors of this text have tried to demonstrate the applicability of "intelligent software" in the realm of analytical chemistry and to provide readers with sufficiently detailed information to pursue their own projects. Through a combination of theory and case studies, the authors have been largely successful in accomplishing their goals. The first chapter presents a discussion of the status of automation in analytical laboratories and an introduction to the types of software (expert systems, neural networks, and genetic algorithms) described elsewhere in the book. Schoenmakers provides an overview of several existing artificial intelligence (AI) systems in Chapter 2. These examples illustrate the wide range of applications for expert system technology offered within the analytical laboratory. In Chapter 3 Hans van Leeuwen details the stages involved in the development of expert systems. This chapter suggests some well-founded approaches and problem areas to be considered when developing AI systems. In Chapter 4 Buydens, van Leeuwen, and Ron Wehrens provide a comprehensive literature review of expert system development tools, including AI programming languages such as PROLOG and LISP, expert system shells, and knowl416 A
edge acquisition tools. A number of tables list commercially available development tools along with sources and their underlying concepts. Four case studies are presented by Frans Maris and Rik Hindriks in Chapter 5. Each expert system involves a different aspect of HPLC method development. These case studies are used to describe how expert systems are appraised by their developers and how they are evaluated by users. Analytical chemists might consider how they can apply expert system technology to the analytical method development challenges they face.
This book provides readers with enough information to pursue their own projects. Wehrens describes various adaptive properties of expert systems in Chapter 6. This chapter illustrates how truly intelligent software should cope in a changing environment in which the knowledge base may require modification. This necessity is demonstrated by the need for expert systems to adapt when applied in similar yet slightly different laboratories. In Chapter 7 Wehrens and Buydens describe inductive expert systems. They explain how expert systems might construct their own knowledge base by examining sets of example cases, and they describe the commonly used ID3 algorithm. In Chapter 8 Gerrit Kateman explores the newest aspects of expert system development—genetic algorithms and neural networks. Genetic algorithms apply no heuristic knowledge, but they extract their own rule base from random searches among numerous examples. Neural networks mimic the brain's organizational
Analytical Chemistry, Vol. 66, No. 7, April 1, 1994
structure with interconnected "neurons" that are trained to perform tasks. The use of summary statements preceding each chapter, concluding sections, and extensive bibliographies make the text easy to read. The case studies make this book a particularly good introduction to expert systems. Reviewed by Stephen Davies, Ontario Ministry of the Environment and Energy, Toronto, Ontario, Canada
The New Drug Purity
Drug Stereochemistry: Analytical Methods and Pharmacology, 2nd ed. Irving W. Wainer, Ed. Marcel Dekker 270 Madison Ave. New York, NY 10158 1993, 432 pp., $165
In its early development, chiral chromatography was driven by analytical challenge and academic interest, as reflected by many early publications and monographs on the subject. As chiral chromatography has matured into a discipline, however, the scope of analytical application has rapidly expanded into other major fields of the natural sciences. With the arrival of chiral analytical techniques, drug stereochemistry has commanded new interest. The practice of pharmaceutical science has been forever changed with the discovery of the metabolic and pharmacological differences between enantiomers of chiral drugs. This expanded second edition is a
welcome revision that presents the current analytical methods and pharmacology for enantiomeric drugs. The book covers a wide scope of topics in drug stereochemistry. The introductory section provides a detailed account of the evolution of stereochemistry, followed by a presentation of fundamental concepts. This background enables the reader to appreciate the issues of drug chirality in subsequent discussions on chemical techniques and pharmacological responses. Because the metabolism of drugs at the molecular level involves enzymes, proteins, and receptors that are chiral molecules, the stereochemical attributes of a drug will govern its biotransformation and effects. One section is devoted to pharmacokinetic and pharmacodynamic differences between drug stereoisomers. The use of stereochemically pure drugs is not always a clinical and regulatory requirement. Economically, it is easier to manufacture the racemic mixture of a drug because the production of enantiomerically pure drugs requires additional resources. However, from the pharmaceutical and pharmacodynamic perspectives, drug manufacturers must establish that the enantiomers in the racemic drug do not possess opposite and contraindicative or undesirable effects. Enantiomerically pure drugs must be prescribed if the racemates produce such mixed effects. Chiral analytical techniques are the prerequisite for elucidating the stereochemical influence on the pharmacological effects of a drug. Several chapters present chiral analysis methods, including competitive receptor-antibody binding assays, indirect methods for chromatographic resolution via selective chemical derivatization, and direct methods using various stationary phases based on most of the known separation mechanisms. The material in these chapters is current and provides pharmaceutical scientists and chemists with the means to make a rational choice of analytical methods based on knowledge of drug chemical structures and functionalities. Because the production of enantiomer-
ically pure drugs by chromatographic resolution of the isomers is cost-prohibitive from the standpoint of efficiency, labor, and yield, it is used only as a last resort. The alternatives discussed in this book include various asymmetric synthetic approaches as well as production-scale racemate resolution by crystallization and kinetic resolution. The clinical relevance of chiral drugs and the rationale for considering their development are discussed in a section entitled "Perspectives on the Use of Stereochemically Pure Drugs." A Food and Drug Administration perspective on the development of new stereoisomeric drugs is offered; the control and characterization
BOOKS RECEIVED Advances in Chromatography, Vol. 33 Phyllis R. Brown and Eli Grushka, Eds. Marcel Dekker 270 Madison Ave. New York, NY 10158 1993, 296 pp., $135
This volume contains six contributed chapters on planar chips technology, LC determinations of ligand-biopolymer interactions, expert systems, the use of chromatographic data for pharmacological classification and drug design, fusion reaction chromatography for the analysis of condensed polymers, and enantioselective LC with chiral stationary phases for pharmaceutical analyses. The book is illustrated with photographs, sample chromatograms, and schematic diagrams. References are current through 1992.
This edition presents the current analytical methods Tunneling and pharmacology Scanning Microscopy and for enantiomeric Spectroscopy: Theory, Techniques, and drugs. Applications of the chiral drug as the active ingredient is discussed, and the expected direction of regulatory guidance is proposed. However, this discussion is only one of many regulatory issues that must be considered in shaping the practices of future pharmaceutical science. This book is recommended to practitioners in pharmaceutical industries involved in the development, characterization, and production of chiral drugs, as well as to pharmacokineticists and toxicologists. Students, who often have limited appreciation of the fact that most drugs in today's market are racemates with at least two and maybe several isomers of similar or different pharmacology, will treasure this book as a reference text. Reviewed by Stanley Lam, Par Pharmaceutical, Spring Valley, NY
Dawn A. Bonnell, Ed. VCH Publishers 220 E. 23rd St. New York, NY 10010 1993, 436 pp., $125
This text is intended as a practical guide to the various STM-based surface analytical techniques. Topics include microscope design and operation, theory and methods of tunneling spectroscopy, the structure and preparation of sample and tip surfaces, force microscopy, ballistic electron emission microscopy and the characterization of buried interfaces, applications of STM to electrochemistry, and biological applications. The book is illustrated with numerous scanned images, schematic diagrams, and sample spectra. Appendices include definitions of variables and acronyms as well as numerical calculations of tunneling current.
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