In this new edition of a bestseller, all the contents have been updated and new material has been added, especially in the areas of toxicity testing and high throughput analysis. The authors, all of them employed at Pfizer in the discovery and development of new active substances, discuss the significant parameters and processes important for the absorption, distribution and retention of drug compounds in the body, plus the potential problems created by their transformation into toxic byproducts. They cover everything from the fundamental principles right up to the impact of pharmacokinetic parameters on the discovery of new drugs. While aimed at all those dealing professionally with the development and application of pharmaceutical substances, the readily comprehensible style makes this book equally suitable for students of pharmacy and related subjects.
Table of Contents
Preface. Abbreviations and Symbols. 1. Physicochemistry. 1.1 Physicochemistry and Pharmacokinetics. 1.2 Partition and Distribution Coefficient as Measures of Lipophilicity. 1.3 Limitations on the Use of 1-Octanol. 1.4 Further Understanding of Log P. 1.4.1 Unravelling the Principal Contributions to Log P. 1.4.2 Hydrogen Bonding. 1.4.3 Molecular Size and Shape. 1.5 Alternative Lipophilicity Scales. 1.5.1 Different Solvent Systems. 1.5.2 Chromatographic Approaches. 1.5.3 Liposome Partitioning. 1.6 Computational Approaches to Lipophilicity. 1.7 Membrane Systems to Study Drug Behaviour. 1.8 Dissolution and Solubility. 1.8.1 Why Measure Solubility? 1.8.2 Calculated Solubility. 1.9 Ionisation (pKa). 2. Pharmacokinetics. 2.1 Setting the Scene. 2.2 Intravenous Administration: Volume of Distribution. 2.3 Intravenous Administration: Clearance. 2.4 Intravenous Administration: Clearance and Half-life. 2.5 Intravenous Administration: Infusion. 2.6 Oral Administration. 2.7 Repeated Doses. 2.8 Development of the Unbound (Free) Drug Model. 2.9 Unbound Drug and Drug Action. 2.10 Unbound Drug Model and Barriers to Equilibrium. 2.11 Slow Offset Compounds. 2.12 Factors Governing Unbound Drug Concentration. 3. Absorption. 3.1 The Absorption Process. 3.2 Dissolution. 3.3 Membrane Transfer. 3.4 Barriers to Membrane Transfer. 3.5 Models for Absorption Estimation. 3.6 Estimation of Absorption Potential. 3.7 Computational Approaches. 4. Distribution. 4.1 Membrane Transfer Access to the Target. 4.2 Brain Penetration. 4.3 Volume of Distribution and Duration. 4.4 Distribution and T max . 5. Clearance. 5.1 The Clearance Processes. 5.2 Role of Transport Proteins in Drug Clearance. 5.3 Interplay Between Metabolic and Renal Clearance. 5.4 Role of Lipophilicity in Drug Clearance. 6. Renal Clearance. 6.1 Kidney Anatomy and Function. 6.2 Lipophilicity and Reabsorption bu the Kidney. 6.3 Effect of Charge on renal Clearance. 6.4 Plasma Protein Binding and Renal Clearance. 6.5 Balancing Renal Clearance and Absorption. 6.6 Renal Clearance and Drug Design. 7. Metabolic (Hepatic) Clearance. 7.1 Function of Metabolism (Biotransformation). 7.2 Cytochrome. 7.2.1 Catalytic Selectivity of CYP2D6. 7.2.2 Catalytic Selectivity of CYP2C9. 7.2.3 Catalytic Selectivity of CYP3A4. 7.3 Other Oxidative Metabolism Processes. 7.4 Oxidative Metabolism and Drug Design. 7.5 Non-Specific Esterases. 7.5.1 Function of Esterases. 7.5.2 Ester Drugs as Intravenous and Topical Agents. 7.6 Prodrugs to Aid Membrane Transfer. 7.7 Enzymes Catalysing Drug Conjugation. 7.7.1 Glucuronyl and Sulpho-Transferases. 7.7.2 Methyl Transferases. 7.7.3 Glutathione S-Transferases. 7.8 Stability to Conjugation Processes. 7.9 Pharmacodynamics and Conjugation. 8. Toxicity. 8.1 Toxicity Findings. 8.1.1 Pharmacophore-induced Toxicity. 8.1.2 Structure-related Toxicity. 8.1.3 Metabolism-induced Toxicity. 8.2 Importance of Dose Size. 8.3 Expoxides. 8.4 Quinone Imines. 8.5 Nitrenium Ions. 8.6 Iminium Ions. 8.7 Hydroxylamines. 8.8 Thiophene Rings. 8.9 Thioureas. 8.10 Chloroquinolines. 8.11 Stratification of Toxicity. 8.12 Toxicity Prediction: Computational Toxicology. 8.13 Toxicogenomics. 8.14 Enzyme Induction (CYP3A4) and Drug Design. 8.15 Enzyme Inhibition and Drug Design. 9. Inter-Species Scaling. 9.1 Objectives of Inter-Species Scaling. 9.2 Allometric Scaling. 9.2.1 Volume of Distribution. 9.2.2 Clearance. 9.3 Species Scaling: Adjusting for Maximum Life Span Potential. 9.4 Species Scaling: Incorporating Differences in Metabolic Clearance. 9.5 Inter-Species Scaling for Clearance by Hepatic Uptake. 9.6 Elimination Half-Life. 9.7 Scaling to Pharmacological Effect. 9.8 Single Animal Scaling. 10. High(er) throughput ADME Studies. 10.1 The High-Throughput Screening (HTS) Trend. 10.2 Drug Metabolism and Discovery Screening Sequences. 10.3 Physicochemistry. 10.3.1 Solubility. 10.3.2 Lipophilicity. 10.4 Absorption/Permeability. 10.5 Pharmacokinetics. 10.6 Metabolism and Inhibition. 10.7 The Concept of ADME Space. 10.8 Computational Approaches in PK and Metabolism. 10.8.1 QSPR and QSMR. 10.8.2 PK Predictions Using QSAR and Neural Networks. 10.8.3 Is In Silico Meeting Medicinal chemistry Needs in ADME Prediction? 10.8.4 Physiologically-Based Pharmacolinetic (PBPK) Modelling. 10.9 Outlook. Index.
Dennis Smith has worked in the pharmaceutical industry for the past 30 years since gaining his Ph.D. from the University of Manchester. For the last 18 years he has been at Pfizer global research and Development, Sandwich where he is vice President-Pharmacokinetics, Dynamics and Metabolism. His research interests and publications span all aspects of Drug Discovery and Development particularly where drug metabolism knowledge can impact on the design of more efficacious and safer drugs. During this 30-year span he has helped in the Discovery and Development of eight marketed NCEs, with hopefully several more to come. He has authored over 100 publications. He is active in a teaching role holding appointments as visiting Professor at the University of Liverpool and Honorary Senior Lecturer at the University of Aberdeen and lectures widely to students at several other Universities. His wish in much of his work is "to inspire another generation to take up the cudgel against disease". Han van de Waterbeemd studied physical organic chemistry at the Technical University of Eindhoven and did a Ph.D. in medicinal chemistry at the University of Leiden, The Netherlands. After a post-doc with Bernard Testa at the University of Lausanne, Switzerland, he became a faculty member for 5 years and taught medicinal chemistry to pharmacy students at the universities of Berne and Basel, Switzerland. In his pharmaceutical career he worked for Roche, Pfizer and Astra-Zeneca where he is now global project leader of their platform for in silico predictions of ADME/Tax properties. He published more than 133 peer reviewed papers and book chapters, and (co-) edited 11 books. His research interests include the role of physicochemical and structural molecular properties in drug disposition and in silico modeling of ADMET properties. Don Walker has a degree in Biochemistry from the University of London and spent four years assisting research involving the biochemistry of inborn errors of metabolism. He joined the Drug Metabolism Department at Pfizer in Sandwich in 1986 and since then has contributed to the drug metabolism and pharmacokinetic evaluations on several drug discovery and development projects including amlodopine, dofetilide, sildenafil, variconazole and maraviroc. He has published numerous papers on drug metabolism and pharmacokinetics and during his career at Pfizer he has been an active contributor to the UK Drug Metabolism Discussion Group, at various times having served as committee member, chairman and course tutor.