[Pharmacokinetics of Zoledronic acid[once-yearly bisphosphonate(intravenous infusion)].]

Zoledronic acid hydrate(zoledronic acid)is an osteoporosis therapeutic agent which shows the fracture suppression effect with once-yearly intravenous infusion. Although zoledronic acid is quickly disappeared from the blood after intravenous infusion, it is taken into the bone immediately and incorporated into the bone tissue. In addition, zoledronic acid shows the potent suppression effect on bone resorption by inhibiting farnesyl diphosphate synthase of the mevalonate pathway(FPPS)strongly. In vivo study, the single intravenous administration of zoledronic acid to the mature ovariectomized(OVX)rats demonstrated to suppress the decreasing bone strength dose-dependently in 32 weeks, corresponding to more than one year in human. Changes in bone resorption markers in the study of Japanese osteoporosis patients(ZONE Study)indicated that bone resorption inhibition action was maintained also over one year. The fracture suppression and increase of bone density with once-yealy administration was demonstrated in clinical trials in the osteoporosis patients in Japan and other countries, and zoledronic acid was currently approved for osteoporosis in September 2016 in Japan. Zoledronic acid is expected to contribute to the treatment of osteoporosis as a new bisphosphonate with once-yearly administration.