Recent Developments in the Design of Orally Bioavailable β3-Adrenergic Receptor Agonists

The β3-adrenergic receptor (β3-AR) has been shown to mediate various pharmacological and physiological effects such as lipolysis, thermogenesis, and relaxation of the urinary bladder. Activation of the β3-AR is thought to be a possible approach for the treatment of obesity, type 2 diabetes mellitus, and frequent urination. Therefore, the β3-AR is recognized as an attractive target for drug discovery. On the other hand, activation of the β1- or β2-AR can cause undesirable side effects such as increased heart rate or muscle tremors. Consequently, a number of recent efforts in this field have been directed toward the design of selective agonists for the β3-AR. This review summarizes recent advances in β3-AR agonists with an emphasis on recent attempts to create potent, selective and orally bioavailable small-molecule agonists.