Bioavailability

The peroral application (swallowing) of a medicine means that the body must first resorb the active substance before it can begin to take effect. The efficacy of drug uptake depends on the one hand on the chemical characteristics of the active substance, above all on its solubility and membrane permeability. On the other hand, it is determined by the organism's ability to absorb pharmaceuticals by way of specific transport proteins or to excrete them. Since many pharmacologically active substances are poorly suited for oral intake, a decisive criterion for the efficacy of a medicine is its so-called bioavailability. Written by an international team from academia and the pharmaceutical industry, this book covers all aspects of the oral bioavailability of medicines. The focus is placed on methods for determining the parameters relevant to bioavailability. These range from modern physicochemical techniques via biological studies in vitro and in vivo right up to computer-aided predictions. The authors specifically address possibilities for optimizing bioavailability during the early screening stage for the active substance. Its clear structure and comprehensive coverage make this book equally suitable for researchers and lecturers in industry and teaching.

This practical book provides crucial information necessary to formulate diets with appropriate amounts of amino acids, minerals, and vitamins. The factors that influence how well animals obtain these critical nutrients and methods for determining bioavailability are reviewed in this comprehensive text. In addition, data from both ruminants and nonruminants are included as well as established estimates of bioavailability for particular feed stuffs and feed supplements.

Understand and assess the design, delivery, and efficacy of orally administered drugs A practical guide to understanding oral bioavailability, one of the major hurdles in drug development and delivery, Oral Bioavailability: Basic Principles, Advanced Concepts, and Applications is designed to help chemists, biologists, life science researchers, pharmaceutical scientists, pharmacologists, clinicians, and graduate and students become familiar with the fundamentals and practices of the science of oral bioavailability. The difference in rate and extent between a drug taken orally and the actual amount of a drug reaching the circulatory system, oral bioavailability is an essential parameter for determining the efficacy and adverse effects of new and developing medications, as well as finding an optimal dosing regimen. This book provides a much-needed one-stop resource to help readers better understand and appreciate the many facets and complex problems of oral bioavailability, including the basic barriers to oral bioavailability, the methods used to determine relevant parameters, and the challenges of drug delivery. In addition, this comprehensive book discusses biological and physicochemical methods for improving bioavailability, integrates physicochemistry with physiology and molecular biology, and includes several state-of-the-art technologies and approaches Caco-2 cell culture model, MDCK, and other related cell culture models which are used to study the science of oral bioavailability.

This authoritative volume explores advances in the techniques used to measure percutaneous penetration of drugs and chemicals to assess bioavailability and bioequivalence and discusses how they have been used in clinical and scientific investigations. Seven comprehensive sections examine topics including in vitro drug release, topical drugs products, clinical studies, and guidelines and workshop reports, among others. The book also describes how targeted transdermal drug delivery and more sophisticated mathematical modelling can aid in understanding the bioavailability of transdermal drugs. The first edition of this book was an important reference guide for researchers working to define the effectiveness and safety of drugs and chemicals that penetrated the skin. This second edition contains cutting-edge advances in the field and is a key resource to those seeking to define the bioavailability and bioequivalence of percutaneously active compounds to improve scientific and clinical investigation and regulation.

Preeminent Experts Update a Well-Respected BookTaking into account the regulatory and scientific developments that have occurred since the second edition, Design and Analysis of Bioavailability and Bioequivalence Studies, Third Edition provides a complete presentation of the latest progress of activities and results in bioavailability and bioequiva

To achieve and maintain optimal health, it is essential that the vitamins in foods are present in sufficient quantity and are in a form that the body can assimilate. Vitamins inFoods: Analysis, Bioavailability, and Stability presents the latest information about vitamins and their analysis, bioavailability, and stability in foods.

Practical and provocative, Bioavailability reviews prevalent understanding of the physical-chemical-biological mechanisms that control the bioavailability of both organic and inorganic contaminants in aquatic environments. Discusses the complex issues that surround many regulatory issues Emphasizes the need to identify and control that portion of the total concentration that is biologically available and can cause adverse effects, i.e., "active" Examines the influence of dynamic factors, such as pH, alkalinity, and light on these mechanisms Addresses the subject of speciation for both organic and inorganic contaminants

This book covers all aspects of bioavailability, as related to environmental contaminants. After a discussion of the definition of bioavailability and its context, focus is placed on the role of risk assessment and bioavailability. Methods of analysis are then discussed including a range of atomic spectroscopic and electrochemical techniques for metal analysis and chromatographic approaches for persistent organic pollutants (POPs). The occurrence, properties and eco-toxicity of POPs and metals in the soil/sediment environment are discussed. Particular emphasis is placed on the uptake of POPs and metals by plants (phytoextraction). Examples of POPs and metals in the environment are reviewed. Methods to assess the bioavailability of POPs and metals in the environment are discussed. The particular approaches considered are: non-exhaustive extraction techniques single extraction techniques sequential extraction techniques use of cyclodextrin and surfactants in-vitro gastrointestinal methods including physiological-based extraction test the use of bioasssays including earthworms. Finally, selected case studies highlight the importance of determining the bioavailability of POPs and metals.