Pharmacokinetic and Safety Profiles of Phytoecdysteroids in Mammals

Owing to the wide range of pharmaceutical effects which have been ascribed to ecdysteroids in mammals and the general consensus on their low toxicity in these species, there is currently considerable interest in developing these compounds as drugs to treat a wide range of conditions (as described elsewhere in this book) and as nutritional supplements. Many of the early data were indicative of the considerable potential of ecdysteroids as pharmaceutical agents but were not supported by thorough clinical trials. Some of these are now being performed. A major part of the process (preclinical and clinical) is to establish the pharmacokinetic and safety profiles, along with the best form of delivery of the candidate drug. In this chapter, we give a brief overview of what is entailed in assessing whether the candidate compound and its formulation have the required properties to become an effective drug. We then review the data which are currently available for ecdysteroids in mammalian systems and finally consider what might be done to overcome the low bioavailability of 20-hydroxyecdysone.