ABSTRACT
These words, written by Frazier and Blank in 1954, suggested that the external treatment of skin disorders in the mid-20th century was probably as haphazard as it was in ancient times. Now, more than 50 years later, we have to ask ourselves, “Have things changed that much?” In the first edition of this book we pointed out that the advances in our understanding of the physicochemical properties of formulation systems and their ingredients had resulted in the development of physically, chemically, and biologically stable products that, after two or three years on the shelf, were as potent as they were when they were first manufactured. There were also considerable advances in our knowledge of the skin and the processes that control percutaneous absorption. The ground rules were laid down by Scheuplein and Blank in the late 1960s and early 1970s (Scheuplein and Blank, 1971), and these are updated on a reasonably regular basis (Barry, 1983; Schaefer and Redelmeier, 1996; Roberts et al., 2002; Roberts and Walters, 2008).
