The concept of fractals in the pharmaceutical sciences.

An old problem is sometimes better understood when it is viewed from a new perspective than by investigating it repeatedly with classical methods. Such a new perspective is provided by the concept of fractals. Briefly, this term defines a spread class of geometric shapes, whose subunits replicate the structure of the larger unit in accordance with the formalization of the idea of self-similarity. This concept was introduced by Mandel-brot in respond to the need for a more sophisticated explanation of numerous phenomena commonly encountered in nature. In this review we will provide a short introduction into the concept of fractals and a concise overview of those studies where fractal geometry has been employed so far in pharmaceutical research. We believe that a review of the most recent findings in the application of fractal geometry to problems encountered in the pharmaceutical sciences might be helpful also to those people who are involved in the search for novel drug substances, as well as in the investigation of their performance in vitro and in vivo. A few suggestions will be made where this concept probably could be helpful in the future and instructions will be given on how the fractal dimension of rugged objects can be estimated practically.