SYNOPSIS
The hydrogel formation of bisphosphonate was investigated after the immersion of apatite coated titanium web (TW) in bisphosphonate solution. Apatite thin film was coated onto TW (porosity of 85 %, pore size of 200-300µm) using molecular precursor method. Molecular precursor solution was obtained by adding dibutylammonium diphosphate salt to Ca-EDTA/amine ethanol solution by adjusting Ca/P=1.67. Sintered cylindrical TW (2.8mm diameter x 6 mm length) was immersed into molecular precursor solution and then heated at 600 ^oC for 2 hr. The immersion and heating process was repeated three times. Uncoated and apatite coated TW were immersed into the bisphosphonate solution (pamidronate disodium, 1x10^-2M) for 24 hr at 37 ^oC. The viscosity of bisphosphonate solution in apatite coated TW was increased. The formation of hydrogel was clearly observed around the apatite coated TW after taking out it from the bisphosphonate solution. It is expected that apatite coated TW will contribute the hydrogel formation of molecules with phosphate groups.

Key words: bisphosphonate, titanium web, molecular precursor method, apatite coating, hydrogel