1998 Volume 46 Issue 11 Pages 1703-1709
Two new series of fused aza-heteroarylbisphosphonates (5, 8), which are structurally quite different from incadronate (YM175), and related compounds were synthesized and evaluated for antiresorptive activity using a parathyroid hormone (PTH)-induced hypercalcemia model in rats (PIH model). Among these compounds, several exhibited more potent antiresorptive activity than pamidronate. In particular, [1-hydroxy-2-(imidazo[1, 2-α]pyridin-3-yl)ethylidene]bisphosphonic acid (5b, minodronate) was 100-fold more potent than pamidronate in not only the PIH model, but also in an immobilization bone atrophy model in rats (DA model), and was selected for clinical development. The structure-activity relationships in these new series of bisphosphonates are discussed.