Small molecule 11β-hydroxysteroid dehydrogenase type 1 inhibitors

11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) catalyzes the interconversion of inactive cortisone to active cortisol in a NADPH dependent manner. Excess cortisol or 11β-HSD1 leads to insulin resistance and metabolic syndrome. Inhibition of 11β-HSD1 activity has been pursued vigorously by the pharmaceutical industry as a potential therapeutic strategy for the treatment of type 2 diabetes. As a result, a large number of chemical classes have been identified as potent and selective small molecule inhibitors for 11β-HSD1. Here we review the recent progress in the discovery and development of small molecule inhibitors of 11β-HSD1 by highlighting the medicinal chemistry, SAR, in vivo pharmacodynamic effects and efficacy of a few representative classes of inhibitors in models of diabetes. Furthermore, we also review the structural characteristics of each class of inhibitors by analyzing the inhibitor co-crystal structures of 11β-HSD1.