Bernard Testa – författare

Drug Bioavailability In order to reach its intended site of action, the drug molecules in every pill that we swallow must first be absorbed, transported via the bloodstream and evade various mechanisms that eliminate drugs from the body. Those drug properties that determine, for example, its stability in the gut or its ease of uptake into the bloodstream, are therefore of central importance in drug development. In fact, many potentially useful drugs fail because of insufficient availability at the biological target site. This second edition of the gold standard for industrial research is thoroughly revised in line with current trends in the field, with all contributions extensively updated or rewritten. No other publication offers the same level of treatment on this crucial topic. In 22 chapters readers can benefit from the key working knowledge of today’s leading pharmaceutical companies, including Pfizer, AstraZeneca, and Roche. Drug developers from industry and academia present all the factors governing drug bioavailability, complete with practical examples and real-life data. Part I focuses on solubility and gastrointestinal absorption, while the second discusses in vitro and in vivo measurements of physicochemical properties, such as membrane permeability and solubility. Part III is devoted to metabolism and excretory mechanisms. The much revised and expanded Part IV surveys current in silico approaches to predict drug properties needed to estimate the bioavailability of any new drug candidate. The final part shows new drug development approaches as well as delivery strategies. Indispensable for all those working in the pharmaceutical industry, pharmaceutical and medicinal chemists, and toxicologists.

This book aims to guide and inspire drug researchers as they enter the 21st century. Stereochemistry is an essential dimension in pharmacology and should be understood as such by all drug researchers whatever their background. When used as probes or medicines, stereoisomeric drugs offer invaluable insights or innovative therapeutic strategies. The book spans the subject from the molecular to the clinical. The first section on chemical aspects contains chapters on chemical synthesis, analysis, natural products, chiral stability (racemezation) and physical properties. The second section is on experimental pharmacology, with chapters on drug-receptor interactions, chiral recognition, ion channels, and molecular toxicology. The third section focuses on drug disposition, with chapters on absorption, distribution, protein binding, metabolism and elimination. The final section is dedicated to regulatory and clinical aspects.

State-of-the-Art Chirality Stereochemistry in general and chirality in particular have long been recog- nized as major structural factors influencing pharmacological activity and pharmacokinetic behavior. For more than a century, relevant information in these fields has been accumulating at an accelerating pace, leading to rationalizations, concepts and theories of increasing breadth and depth. Frequently, fundamental advances in stereochemical aspects of molecular pharmacology, drug disposition and pharmacochemistry have been translated into corresponding progress in clinical pharmacology and pharmacotherapy. There have been exceptions, however, since some extrapolations from the biochemical and in vitro situations to the in vivo human situation have proven premature. This notion resulted in the now appeased, but far from closed, debate regarding racemic versus enantiopure drugs, which saw some pro- ponents state that "in many cases, only one isomer contributes to the thera- peutic action while the other, the 'isomeric ballast', only contributes to the side effects and toxicity" (ARIENS 1986,1989,1992).Other authors, in contrast, have cautioned against hasty generalizations and advocated a more pragmatic, case- by-case and evidence-based view (CALDWELL 1995; DE CAMP 1989; SZELENYI et al. 1998; TESTA 1991; TESTA and TRAGER 1990; TESTA et al. 1993).