Effect of Chondroitin Sulfate on the Precipitate Formation of Calcium Phosphate in Water

概要

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The properties of calcium phosphate (CaPi) formed in supersaturated solution (prepared by mixing CaCl_2 and K_2HPO_4 at neutral pH) were studied by means of a Coulter counter and a calcium ion-specific electrode. It was found that the mean particle diameter (φ) of CaPi formed initially increased and then levelled off with time. The rate of increase of φ, however, decreased with increase in the amount of sodium chondroitin-6-sulfate (Na_2Chs) added to the mother solution, presumably because of the dispersing effect of Na_2Chs. The number concentration of formed particles of CaPi increased at first but after a short period it decreased with time because of the formation and aggregation of secondary particles. Remarkable consumption of Ca^<2+> was observed at two points in the time course of the precipitation reaction : (1) immediately after mixing the reactants, and (2) after and induction period (t_<trans> required for the crystallization of amorphous CaPi as hydroxyapatite (HAP), as was confirmed by measurement of the X-ray powder diffraction pattern. The lag time, t_<trans>, was not affected by the amount of Na_2Chs added, but decreased with increase in the amount of CaPi precipitated or of seed HAP inoculated. The physiological significance of the present work is briefly discussed.
公益社団法人日本薬学会の論文
1985-09-25