Solid-state NMR of bisphosphonates adsorbed on hydroxyapatite

✍ Scribed by Gisbert Grossmann; André Grossmann; Gisela Ohms; Eli Breuer; Ravit Chen; Gershon Golomb; Hagit Cohen; Gerhard Hägele; Ralph Classen

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 111 KB
• Volume: 38
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/(sici)1097-458x(200001)38:1<11::aid-mrc597>3.0.co;2-v

✦ Synopsis

Solid-state 31 P and 13 C magic angle spinning (MAS) NMR spectra were used to characterize pure bisphosphonates and also bisphosphonates adsorbed on hydroxyapatite. Four geminal bisphosphonates, including the clinically used compounds ethane-1-hydroxy-1,1-diphosphonic acid, 3-amino-1-hydroxypropane-1,1-diphosphonic acid and 4-amino-1-hydroxybutane-1,1-diphosphonic acid, five ˛,ω-bisphosphonates and phosphonoacetic acid were investigated. NMR spectra of pure and adsorbed bisphosphonates differ in the observed linewidths and in the isotropic chemical shifts. The broad lines reflect mainly the poor crystallinity of the adsorbed compounds. Shifts of υ iso in both directions do not reveal a correlation with the molecular structures. The molar ratio of phosphonates adsorbed on hydroxyapatite determined by 31 P spectra without cross-polarization (CP) is approximately two times larger for geminal bisphosphonates than for ˛,ω-bisphosphonates and phosphonoacetic acid. 13 C CP/MAS spectra of pure and adsorbed bisphosphonates recorded in two cases for identification of adsorbed compounds give additional information about the state of adsorbed compounds. Disodium ˛,ω-dihydroxypolymethylene-˛,ω-bisphosphonates in the solid state show characteristic 13 C chemical shifts which are indicative of either odd or even numbers of CH 2 groups.