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Chapter Wang and Robert O. Williams III,   411Particle Size Reduction   426Properties of Powders   411Powder Handling   428Bulk Properties of Powders   419Powders as a Dosage Form  432Production Methods   applications are expanding in a variety of highly developed fields, such as foods, cosmetics, chemicals, and fundamental fields, particularly in pharmaceuticals. of active pharmaceutical ingredients (APIs) are administered as solid dosage forms, prepared by processing and formation of powders. A powder is defined as a dry, solid substance,.consisting of a large number of finely divided particles (), and typically obtained by crushing, grinding,.or Powders have a large specific surface surface free energy, therefore, exhibiting some physical properties. Some of the properties related to pharmaceutics, such as particle size, shape, surface area, density, porosity, flowablility, will influence the forming, packing, and processing of a variety of dosage forms, . granules, tablets, capsules,.suspensions, etc. Additionally, the solubility and a drug formulation can be affected by some basic characteristics of powders as well. Besides acting as pharmaceutical excipients, such as diluents, disintegrating agents, and lubricants,.powders can also present as a pharmaceutical dosage form. , powders are fundamental to pharmaceutics, a significant impact on the development, manufacture,.quality control, and packing of a variety of dosage forms, including tablets, capsules, granules, suspensions, microcapsules,.microspheres, and dry powder inhalers (DPIs). This chapter to provide a comprehensive understanding of powders,.including fundamental properties of powders, primary powder production, handling, and powders as a dosage of CharacterizationParticle size is a basic property of a powder, which is powder technology and dosage form design. Particles size and size distributions exhibit different behaviorsFor instance, smaller particles have greater specific and their bulk density, porosity, flowability, and differ from that of larger particlesDefinition and Expression of Particle size, typically expressed as particle diameter, is characterizing powders. A powder is a plurality of solid particles; powders prepared using different methods, or by the , vary greatly in size and shape. The size of a single particle, having an ordinary spherical or cube shape, can be the diameter of a sphere or the length of a cube side. However,.the majority of particles in a powder are non-spherical and irregular. As particle shape becomes more irregular, expressing the an individual particle is even more difficult. To fulfill the production and research, scientists use a number of for particle size, based on size measurementThe physical meaning of different particle size expressions in Table Herein Feret’s and Martin’s diameter to express the geometric size of powder particles. Feret’sdiameter refers to a diameter measured between imaginary parallel lines tangential to a randomly oriented particle and perpendicular to the scale of measurement; Martin’s diameter refers diameter measured from the length of the particle at the divides a particle into two equal projected These diameters that depend on both the orientation direction of particles. For irregularly shaped particles,.a sphere with the same projected surface area or volume as the equivalent sphere of the irregular particles, diameter of the irregular particles can be expres

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