Bone targeting for the treatment of osteoporosis

Osteoporosis represents a major public health burden especially considering the aging populations worldwide. Drug targeting will be important to better meet these challenges and direct the full therapeutic potential of therapeutics to their intended site of action. This review has been organized in modules, such that scientists working in the field can easily gain specific insight in the field of bone targeting for the drug class they are interested in. We review currently approved and emerging treatment options for osteoporosis and discuss these in light of the benefit these would gain from advanced targeting. In addition, established targeting strategies are reviewed and novel opportunities as well as promising areas are presented along with pharmaceutical strategies how to render novel composites consisting of a drug and a targeting moiety responsive to bone-specific or disease-specific environmental stimuli. Successful implementation of these principles into drug development programs for osteoporosis will substantially contribute to the clinical success of anti-catabolic and anabolic drugs of the future.

Composition of bone. (a) Long bones are composed of trabecular bone within the bone cavities that contains the bone marrow and cortical bone on the outer shell, which forms compact layers around. (b) Trabecular bone is composite of a porous network, where bone cells such as endosteal osteoblasts and osteoclasts are in close contact to the bone marrow. Vascular sinusoids are located in close distance to the endosteum. Mesenchymal stem cells (MSC) and hematopoietic stem cells (HSC) are situated next to sinusoids but are also found at the bone surface (not shown).Figure optionsDownload high-quality image (186 K)Download as PowerPoint slide