Abstract： Superfine pentoxyverine citrate powders were prepared by spray drying process. Orthogonal experiments were designed to research the effect of technical parameters on particle size distribution and optimize the preparation process. Micro-structure and micro-morphology of the superfine powders were studied by XRD and SEM, and the process of crystallization was analyzed. The results show that the optimum process conditions for superfine pentoxyverine citrate powders are that the mass concentration in drug suspension is 0.03 g/mL, the input temperature is 170 ℃, and the spray rate is 400 mL/h. During the spray drying process, the phase structure of previous pentoxyverine citrate of solid state does not change, and the particles exhibit flake shape. Part of solute remains the initial phase structure and crystallizes at liquid-solid interface, and the phase structure of others changes into amorphous state, micro-morphology of the later mainly presents spherical particles.

Keywords: spray drying； pentoxyverine citrate; particle size distribution; micro-structure; micro-morphology