Editing Bisphosphonate (section)

==Chemical structure and mechanistic aspects==
The term bisphosphonate refers to the presence two [[phosphonate]] ({{chem2|PO2(OH)-}}) groups. They are also called '''diphosphonates''' (''[[wikt:bis-#Prefix|bis-]]'' or ''[[wikt:di-#Prefix|di-]]'' + ''[[phosphonate]]'').  The {{chem2|PO2(OH)-}} groups readily lose an additional proton giving ({{chem2|PO3(2-)}} groups, which have a particular high affinity for metal ions.


They are structurally close analogues of [[pyrophosphate]] (abbreviated PP<sub>i</sub>).<ref>{{cite journal |doi=10.1016/j.bone.2011.04.022 |title=Bisphosphonates: The first 40years |date=2011 |last1=Russell |first1=R. Graham G. |journal=Bone |volume=49 |issue=1 |pages=2–19 |pmid=21555003 }}</ref>. Like pyrophosphate, bisphosphonates inhibit the growth and dissoliution of bone.  Unlike pyrophosphate, bis(phosphonates) are very stable in aqueous solution.  They resist break down by hydrolysis because the P-C-P or P-N-P linkages are more robust than P-O-P linkages. Bis(phosponate)s are proposed to interfere with osteoclasts, which cause bone resorption.