Influence of Physicochemical Properties on Ball-Milling of Pharmaceutical Powders

概要

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Ball-milling of thirty-two kinds of powders were investigated. Equation (1) was applied for rate of increase of surface area. dS/dt=k_1 exp (- k_2S) (1) Parameter k_1 was proportional to 1/Mohrs'es hardness and tended to be small for the samples with high melting point. Rarameter k_2 was small for the sample with high melting point and little solubility in water. Critical particle size, Dc_2,was found at which maximum porosity in loosest packing was obtained not only for crushed samples but for samples of equal particle size. For particles below Dc_2,gravitational force of a particle may be negligibly small compared with cohesive force between particles. D_<min> was proportional to Dc_2. Parameter k_1 tended to decrease and k_2 to increase with increase of ρ・D_<min>. Rate of increase of surface area by ball-milling is considered to depend on coherency of powder particles expressed as a function of surface energy, melting point, solubility in water, true density and so on.
公益社団法人日本薬学会の論文
1971-05-25