Design, synthesis, and biological evaluation of novel estradiol-bisphosphonate conjugates as bone-specific estrogens.

Bone deficiency causes osteoporosis and often decreases quality of life in patients with rheumatoid arthritis. Estrogens are known to protect elderly women from bone loss. Synthesis of new estradiol-bisphosphonate conjugates (E(2)-BPs) was accomplished and their in vivo activity as bone-specific estrogens were examined.