Bisphosphonate protonation states, conformations, and dynamics on bone mineral probed by solid-state NMR without isotope enrichment

Structural Requirements for Bisphosphonate Binding on Hydroxyapatite: NMR Study of Bisphosphonate Partial Esters

“…BPs’ affinity for bone depends highly on their structure . The binding is mainly mediated by the two phosphonate groups, but other properties are thought to contribute to the binding affinity as well, for example, a hydroxyl group as substituent R 1 or a primary amine group in the substituent R 2 . Several different methods have been utilized to assess BPs’ affinity for hydroxyapatite (HAP) and bone powder .…”

“…5 The binding is mainly mediated by the two phosphonate groups, but other properties are thought to contribute to the binding affinity as well, for example, a hydroxyl group as substituent R 1 or a primary amine group in the substituent R 2 . 6 Several different methods have been utilized to assess BPs' affinity for hydroxyapatite (HAP) and bone powder. 7 These methods include solid-state NMR spectroscopy, 8 constant composition kinetic studies of crystal growth 5,9 and fast performance liquid chromatography with HAP columns.…”

Stable surface functionalization of carbonized mesoporous silicon

“…In addition to the main resonance, decomposition of the signal suggests at least three other components at −11, 1 and 11 ppm indicating different protonation states, conformations or possible side products of the grafting reaction. 38 The sharp resonance at 1 ppm corresponds to the silylated bisphosphonate based on liquid state NMR indicating that some silyl groups that were used as protective groups during the functionalization remained in the material.…”

Smart, programmable and responsive injectable hydrogels for controlled release of cargo osteoporosis drugs

“…Furthermore, the bands assigned to the R-(CH 2 ) x -NH 3 + moiety (in the regime >3000 cm −1 ) broaden and are undetectable in the dried gel spectra. Regarding the protonation state of the BPs, it is certain (from literature reports 36–38 ) that at pH 7 (the pH of the internal gel regions) each phosphonate moiety is mono-deprotonated (–PO 3 H − ), and (for the aminoalkyl BPs) the amine moiety is protonated (R-(CH 2 ) x -NH 3 + ).…”