In the spirit of understanding how drugs work, this textbook explores the fundamental physicochemical attributes and processes important for understanding how a drug, usually in the form of a crystal, is transformed into a usable product that is administered to a patient to reach its pharmacological target, and then leaves the body. This is the discipline of physical pharmacy—the study of the physical and chemical properties of drugs and their dosage forms. When integrated with other critical knowledge of how drugs work, such as their pharmacologic effects, physical pharmacy forms part of the scientific foundation for the clinical sciences and, therefore, for clinical practice. A distinguishing feature of physical pharmacy is that, unlike pharmacology, which is learned to different degrees by other healthcare practitioners, physical pharmacy is a body of knowledge unique to the education of student pharmacists, for whom this textbook is written. It provides the physicochemical basis for rational formulation, manufacturing, compounding, drug delivery, product selection, and product usage. Therefore, it is knowledge indispensable for the ability of the pharmacist to comprehensively understand and explain how drugs work, in a manner and to an extent that is unparalleled by any other healthcare practitioner. In other words, it's a part of the body of knowledge that equips pharmacists with unique perspectives and insights in the provision of pharmaceutical care.
Significant revisions have been made from the first edition of Applied Physical Pharmacy published in 2003, including addition of clinical examples and applications that are relevant in contemporary pharmacy practice. Each chapter includes a set of Learning Objectives to guide the student's focus in learning, Key Points to delineate the critical concepts discussed in the chapters, Problems to apply and assess the understanding of chapter concepts, and Clinical Questions to apply the chapter concepts in a clinical context.
An overarching goal in the writing and editing of this edition was to improve its focus on the critical knowledge needed for the education of the student pharmacist. The number of chapters was reduced from 13 to 11. Chapters with conceptually common material were blended into new chapters. Each chapter was examined for relevance to pharmacy education, and was accordingly edited to help achieve this goal. Some of the material from the first edition that was considered important but more relevant to graduate work in physical pharmacy was moved to chapter appendices. This was done to improve the flow of material within the chapter, again to make it more conducive for learning by student pharmacists.
The textbook begins with a review of the key biopharmaceutics concepts of drug liberation, absorption, distribution, metabolism, and excretion. These concepts and others set the framework for subsequent chapters that describe physicochemical properties and processes related to the fate of the drug. These include states of matter (Chapter 2), solutions, (Chapter 3), ionization (Chapter 4), dissolution and partitioning (Chapter 5), mass transport (Chapter 6), and complexation and protein binding (Chapter 7). Concepts in these chapters are important not only for understanding a drug's fate in the body but also for providing the scientific basis for rational drug formulation. Other physical pharmacy topics important to drug formulation and usage are discussed in the three chapters that follow, which describe dispersed systems (Chapter 8), interfacial phenomena (Chapter 9), and rheology (Chapter 10). The textbook concludes with an overview of the principles of kinetics (Chapter 11) that are important for understanding the rates at which many of the processes discussed in previous chapters occur. We are very grateful to all of the contributing authors who shared with us their expertise in important physical pharmacy knowledge and skills. A special thanks goes to Michael Weitz, the McGraw-Hill Executive Editor for Medical, Pharmacy & Allied Health Textbooks, for his enormous patience in accommodating our busy schedules, while guiding us to this textbook's conclusion. Thanks also to all of the McGraw-Hill editors, including Karen G. Edmonson. We also thank our pharmacy students who continuously inspire us to improve our craft of teaching. Most importantly, we are each grateful to our families, whose love, support, and patience helped make the writing and editing of this textbook possible and worthwhile.