EP7.0 欧洲药典 2.9.38. Particle-size distribution 粒度分布_中文_翻译.pdfVIP

2.9.38. 筛分法评估颗粒度大小分布(17) PARTICLE-SIZE DISTRIBUTION ESTIMATION BY ANALYTICAL SIEVING(17) 筛分是对粉末和颗粒通过颗粒大小分布进行分级的最老的方法之一。当使用织物 筛布时，筛分基本上依据筛网的中间尺寸大小（即幅度或宽度）对颗粒进行分类。 如果大部分的颗粒大于75 微米左右，采用机筛法是最合适的。对于更小的颗粒， 由于质量轻，在筛分过程中，它们不能克服表面凝聚力和粘附力，使颗粒相互粘 在一起或粘在筛网上，从而导致那些本该能通过筛孔的颗粒而未能通过。对于这 样的材料，其它的振动方式，如喷气筛分或声波筛分器筛分可能更为合适。然而， 筛分有时可被用于一些中值颗粒尺寸小于75 微米的粉末或颗粒，只要该方法经 过验证。在制药行业，对单一粉末或颗粒进行粗略等级分类时，筛分通常是被选 择的方法。这是一个尤其引人注目的方法，因为该方法仅依据粒径大小对粉末和 颗粒进行颗粒大小分级，在大多数情况下，干粉状态下即可进行检测。 Sieving is one of the oldest methods of classifying powders and granules by particle-size distribution. When using a woven sieve cloth, the sieving will essentially sort the particles by their intermediate size dimension (i.e. breadth or width). Mechanical sieving is most suitable where the majority of the particles are larger than about 75 µm. For smaller particles, their light weight provides insufficient force during sieving to overcome the surface forces of cohesion and adhesion that cause the particles to stick to each other and to the sieve, and thus cause particles that would be expected to pass through the sieve to be retained. For such materials other means of agitation such as air-jet sieving or sonic-sifter sieving may be more appropriate. Nevertheless, sieving can sometimes be used for some powders or granules having median particle sizes smaller than 75 µm where the method can be validated. In pharmaceutical terms, sieving is usually the method of choice for classification of the coarser grades of single powders or granules. It is a particularly attractive method in that powders and granules are classified only on the basis of particle size, and in most cases the analysis can be carried out in the dry state. 筛分方法的局限性包括：需要可观质量的样品（通常至少为25 克，这取决于粉 末或颗粒的密度和试验筛的直径）；以及在筛分那些容易堵塞筛孔的油性或有粘 着力的粉末或颗粒时存在困难。该方法在本质上是一个对颗粒大小的两个维度的 估计，因为