Micromeritics PDF

MICROMERITICS Cyruschad B. Tutor, RPh, MBA  Micromeritics science and technology of small particles; study of the particle size and size distribution, shape, angle of repose, porosity, true volume, apparent densit...

MICROMERITICS Cyruschad B. Tutor, RPh, MBA  Micromeritics science and technology of small particles; study of the particle size and size distribution, shape, angle of repose, porosity, true volume, apparent density, and bulkiness" ctutor2024  Colloidal dispersions are characterized by particles that are too small to be seen in the ordinary microscope, whereas the particles of pharmaceutical emulsions and suspensions and the “fines” of powders fall in the range of the optical microscope. Particles having the size of coarser powders, tablet granulations, and granular salts fall within the sieve range. ctutor2024  Properties of Powders FUNDAMENTAL PROPERTIES DERIVED PROPERTIES surface area porosity particle size packing arrangements size distribution density bulkiness ctutor2024  FACTORS AFFECTING THE FLOWABILITY OF POWDERS PARTICLE SIZE AND SHAPE 250-2000 micrometers = free flowing Also affects the packing properties of powders The more asymmetrical a particle is, the greater its surface area but as it gets more asymmetric, the more difficult it is to assign a meaningful diameter. ctutor2024  FACTORS AFFECTING THE FLOWABILITY OF POWDERS POROSITY AND DENSITY High density, low porosity = FREE FLOWING Ideal packing arrangements: rhombohedral and cubic packing ctutor2024  FACTORS AFFECTING THE FLOWABILITY OF POWDERS SURFACE ROUGHNESS Leads to poor flow characteristics ctutor2024  METHODS FOR DETERMINING PARTICLE SIZE Optical microscopy Sedimentation ctutor2024 Sieving  SURFACE AREA The surface area per unit weight or volume is an important characteristic of a powder when one is undertaking surface adsorption and dissolution rate studies. ctutor2024  METHOD TO DETERMINE SURFACE AREA FOR PARTICLE DISTRIBUTION 1.Adsorption method HIGHER ADSORPTION, LARGER SURFACE AREA ctutor2024  METHOD TO DETERMINE SURFACE AREA FOR PARTICLE DISTRIBUTION 2.Air permeability method GREATER AIR FLOW RESISTANCE, THE LARGER THE SURFACE AREA ctutor2024  TERMINOLOGIES USED FOR MICROMERITICS POROSITY: aka void fraction, measure of the void spaces between particles TRUE VOLUME/ DENSITY: density of the actual material exclusive of pores/ voids; can be measured using displacement of Helium BULK VOLUME/ DENSITY: aka apparent density; true volume + void porosity or interspaces GRANULE DENSITY: true volume + intraspaces; can be measured using displacement of Mercury ctutor2024  ANGLE OF REPOSE Refers to the maximum angle formed between a horizontal plane and the surface of a pile of powder or granules at rest. ctutor2024  ANGLE OF REPOSE It is the angle formed between the horizontal surface and the slope of a pile of unconsolidated material when it reaches equilibrium. At this angle, the material is on the verge of sliding or flowing due to the force of gravity. ctutor2024  ANGLE OF REPOSE It provides an indication of the powder's ability to flow freely and its cohesiveness. A lower angle of repose generally suggests better flow properties, while a higher angle indicates poorer flow. ctutor2024  ANGLE OF REPOSE Pharmaceutical powders with good flow properties are essential for consistent and efficient manufacturing processes, particularly in processes like tablet compression. If a powder has poor flowability, it can lead to issues such as inconsistent tablet weight, content uniformity problems, and difficulties in filling capsules. ctutor2024  ANGLE OF REPOSE The angle of repose depends on various factors, including the size, shape, and cohesion of the particles making up the material. Different materials exhibit different angles of repose. For example, dry, coarse sand might have a steeper angle of repose than wet, fine sand. ctutor2024  ANGLE OF REPOSE a relative simple technique for estimating the flow properties of a powder; can easily be determined by allowing a powder to flow though a funnel and fall freely onto a surface. The height and diameter of the resulting cone are measured and the angle of repose calculated as: H (Cone Height cm) tan Ѳ = h/r r (Cone radius) ctutor2024  ANGLE OF REPOSE ctutor2024  COMPUTE ME! 1. H: 120cm D: 350 r 2. H: 12inch D: 130cm 3. H: 560 mm D: 450 r ctutor2024 Thank You!