Introduction to Pharmaceutical Calculations, 3rd Edition

The second edition of Introduction to Pharmaceutical Calculations by Rees, Smith and Smith utilizes a practical approach to pharmaceutical calculations. The merit of this book lies in its systematic approach to problem-solving via the consistent use of proportions. Simple language and technique is used for the stepwise approach to each problem, such as sorting through given data and constructing proportion sets to obtain the required data using simple algebra. The book is divided into 10 chapters, with every chapter helpfully listing a set of learning objectives. Chapters 1 and 2 focus on essential basic tools such as ratios, proportions, fractions and units, including conversions. The next 3 chapters discuss percentage and ratio strengths, dilutions, and increasing and reducing formulae. Chapter 6 involves dose calculations, including calculations based on body weight and body surface area. Density and displacement volumes are discussed in chapter 7, including calculations for displacement value of drugs with respect to various suppository bases. Chapter 8, on calculations involving molecular weights, is an asset. Although armed with a college-level background in chemistry, a surprising number of pharmacy students are frequently found to be less than comfortable with the concepts of atomic and molecular weights, valence, the relationship between free acids/bases and their various salts, and the relationship between anhydrous and hydrated forms of a drug. The next chapter is devoted to parenteral and isotonicity calculations. The last chapter emphasizes the importance of accuracy of measurement. The book ends with a number of appendices on conversions, atomic weights, etc. 
 
As a professional trained in the British system and currently teaching in the American system, I can offer some specific insights into this book's utility in pharmacy education in the United States. First of all, the reader must bear in mind that this is a book authored by British authors and primarily aimed at UK pharmacy programs. Hence, some terminology may not be familiar to US readers, for instance, body weight given in stone and terms such as “paracetamol”, “co-codaprin” or “co-fluampicil”. References are made to British National Formulary dose recommendations. Certain drugs used in the examples are not approved in the United States, such as domperidone, although the drug name or therapeutic indication has no correlation with the skill sets required for dose calculations. The second concern is regarding the methodology, in spite of being classical and (arguably) the logical way of solving problems. Professional education follows high school and early college courses, and teaching methodologies frequently must be adapted to the existing skill set of our students. In adapting this book as a primary text, the educator must be willing to train the students in the methodology utilized, especially the manner in which it is presented in this book, which may be less than conducive to the learning style of the majority of US students who are increasingly comfortable with dimensional analysis. The third concern is the lack of modern clinical context in the examples and practice problems, which include products such as chloroform water, triturates, and pessaries. On the flip side, the text is limited in its coverage of concepts such as milliequivalents, osmolarity, etc. The last concern is the dearth of practice problems. Overall, this is a classical book of pharmaceutical calculations and a useful secondary text for US pharmacy educators and students.

Field of study: Education, Medicine