Otsuka A
Faculty of Pharmacy, Meijo University, Nagoya, Japan.
Yakugaku Zasshi. 1998 Apr;118(4):127-42. doi: 10.1248/yakushi1947.118.4_127.
This report deals with adhesive properties and related phenomena of powdered materials including pharmaceuticals. The adhesive force between a powder particle and substrate as well as the tensile strength of a powder bed and tablet was measured. Various factors were found to affect powder adhesion. Physical properties such as the size, shape and surface roughness were examined. The adhesive force between a particle and substrate decreased remarkably in the presence of ultrafine particles, which is of interest since the addition of adequate amount of "glidant" causes an increase in powder fluidity. From a pharmaceutical point of view, temperature and humidity were essential to particle adhesion. For several organic substances, the adhesive force increased significantly at homologous temperatures more than ca. 0.7, suggesting the sintering mechanism to be operative. The adhsive force between polymer films and glass beads varied according to polymer and relative humidity. A close correlation of water sorbed by the polymer film with adhesive force was noted. In connection with powder fluidity, compaction properties were studied by the centrifugal and tapping methods. Apparent adhesion defined as the ratio of the adhesive force between two contacting particles to the external force acting on a particle was noted to be the primary determinant of the void fraction or the porosity of the powder bed, indicating that the probability of particle displacement essentially depended on apparent adhesion.
本报告涉及包括药物在内的粉末材料的粘附特性及相关现象。测量了粉末颗粒与基材之间的粘附力以及粉末床和片剂的拉伸强度。发现多种因素会影响粉末的粘附。研究了诸如尺寸、形状和表面粗糙度等物理性质。在存在超细颗粒的情况下，颗粒与基材之间的粘附力显著降低，鉴于添加适量的“助流剂”会导致粉末流动性增加，这一点值得关注。从药学角度来看，温度和湿度对颗粒粘附至关重要。对于几种有机物质，在同源温度超过约0.7时，粘附力显著增加，表明烧结机制起作用。聚合物薄膜与玻璃珠之间的粘附力随聚合物和相对湿度而变化。注意到聚合物薄膜吸附的水分与粘附力密切相关。关于粉末流动性，通过离心法和振实法研究了压实特性。定义为两个接触颗粒之间的粘附力与作用在颗粒上的外力之比的表观粘附力被认为是粉末床空隙率或孔隙率的主要决定因素，这表明颗粒位移的可能性基本上取决于表观粘附力。
