JOURNAL OF COSMETIC SCIENCE 362 therapy nevertheless, careful reading of the three chapters in Part IV indicates real- ized and potential cosmetic applications along with important limitations. Part V, “Special Delivery Routes,” be- gins with a chapter by Wiechers describing studies of nicotinate delivery from a sham- poo, evaluating such variables as contact time, drug concentration, and body site. The results suggest that highly permeable molecules could be delivered from a rinse- off product, though with much greater dif- fi culty than from a leave-on product. The next two chapters, Chapter 24 by Grams et al. and Chapter 25 by Cross, describe the current state of knowledge of follicular delivery and methods for its mea- surement. Not only is this important for situations where the target is within the follicles (e.g., acne) but a knowledge of the relative contribution of the various path- ways, including the follicles, is fundamen- tal to our understanding of the permeation process. Most of what we know today about the importance of the follicular route comes from in vitro experiments, which neglect the continuous outward sebum fl ow. Some exciting experiments utilizing nano- and microparticles have been performed, but a great deal of work remains to be done on formulating to target the follicles. The book’s fi nal part, Part VI, is entitled “Future Perspectives.” It begins with a chapter by Schneider on legal aspects of de- livery systems. After providing a list of questions to answer when introducing a new delivery system, the author goes on to describe several test methods for irritation and sensitization and several classes of ac- tives, before getting into a discussion of de- livery systems that includes the importance of safety testing and making proper claims. This is followed by a brief discussion of the regulatory status of nanosized particles. In Chapter 27, Newman discusses as- pects of marketing skin care products, noting that the delivery systems must do more than controlling the release and in- creasing the performance of actives the benefi ts to consumers must be evident. Though we often focus on the properties of the active, delivery systems may add their own benefi ts—for example, in providing miniaturization. In such cases, the delivery system may be more important than the nominal active in producing a benefi cial re- sult. Newman recommends considering the active and delivery system as a unit rather than focusing marketing efforts on the “gee-whiz” value of the delivery system. The fi nal chapter is an overview, “Clini- cal Relevance of Topical Delivery Systems for Active Cosmetic Ingredients” by Thong and Maibach. The focus of this chapter does not match the title, nor does it pro- vide much in the way of a perspective for the future. The authors expound on the importance of in vitro skin penetration studies and the need for better correlation with in vivo data. Table 28.1 lists ten steps in the in vivo percutaneous absorption pro- cess. Table 28.2 lists several penetration- enhancement techniques and Table 28.2 is a non-critical listing of penetration- enhancing chemicals. This book is a comprehensive summary of the current state of the art, although two areas that receive insuffi cient attention are penetration enhancers and tape/patch de- livery systems. As is common with multi- authored volumes, there is some overlap in coverage, but the amount is minimal and does not detract from the book’s message. This book is highly recommended for scientist working on skin care products and OTC drugs. It should be part of the library of every company involved in these areas. —JOEL L. ZATZ—Rutgers University.

BOOK REVIEWS 363 SKIN AGING HANDBOOK, Nava Dayan, Ed. (William Andrew Publishing, 2008), 494 pp. This refreshing book takes a new look at aging skin. The editor, Nava Dayan, brings together knowledge from many different disciplines, including dermatology, sociol- ogy, cosmetic formulation, gerontology, and biochemistry, to deliver a compelling treatise on how skin ages and what can be done from a topical standpoint to positively affect appearance. The text begins with a chapter on aging skin from a sociocultural perspective. As a physician, I found the concept of medical- ization intriguing. Medicalization is the formalization of bodily states and practices that were once handled informally. For ex- ample, aging now has been formalized as a disease requiring medical intervention. Maturity is termed the “third age,” repre- senting the time from retirement to the onset of terminal decline. This shift re- quires medical attention to maintain peak health with advancing age and creates op- portunities for the skin care industry to de- velop products to optimize appearance, the topic of the second chapter. The next interesting chapter, by Andreas Lanitis, is a fascinating look at the world of computer-based aging progression meth- odologies, describing how childhood im- ages are modifi ed to create a picture of the mature face. It is a study in changing facial proportions, accounted for by loss of bone, redistribution of fat, and skin texture ab- normalities. With this introduction, the book launches into Part 2, discussing the biochemical, pharmacological, and ethnicity aspects of aging. Different aspects of aging, including skin barrier anomalies, sebum and epidermal lipid changes, infl ammation, cell senescence, and topical methods of treat- ing skin aging, are discussed. This information is a nice preface for the core of the book, dealing with product de- velopment (Part 3), testing methodologies (Part 4), and regulatory aspects (Part 5). The formulator will fi nd this book indis- pensable as it brings together an under- standing of the aging process and how products should be formulated and tested to meet the needs of the expanding geriat- ric population. Not all skin is the same. Failure to address the needs of mature indi- viduals is a missed opportunity. This text provides the necessary knowledge to allow the formulator to seize this opportunity.— ZOE DIANA DRAELOS—Dermatology Consulting Services.