February 25, 2018
BY Make My Tea0
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MICROMERITICS
Micromeritics is the study of no of characteristics, including particle size and size, distribution, shape, true volume, apparent density And bulkiness.
Knowledge and the control of the size and the size range of particles are of Significant importance in pharmacy because the size and surface area of a particle related to the physical, chemical and pharmacologic properties of a drug.The particle size of a drug can affect its release from dosage forms that are administered orally, parenterally, rectally and topically.In the area of tablet and capsule manufacture, control of the Particle size is essential in achieving the necessary flow properties and proper mixing of granules and powders.
As particle size decreases, area increases.
In
a collection of particles of more than one size,two properties are important,
namely:
1.The
shape and surface are of the individual particles.
2.The
particle size and size distributions (The size arrange and number or weight of
particles.)
Method for determining Particle Size:
Optical
Microscopy.
Sieving.
Sedimentation.
Particle
Volume Measurement.
Optical Microscopy:
(Range:0.2-100 micrometer)
Microscopic
eyepiece is fitted with the micrometer by which the size of the particle can be
estimated.
Sedimentation:
(Range:0.08-300 micrometer)
By
measuring the terminal settling velocity of particles through a liquid medium in a gravitational centrifugal environment using Andreasen
apparatus.
Sieving:
(Range:40-9500 micrometer)
Standard
size sieves are available to cover wide range of size.These
sieves are designed to sit in a stack so that material falls through smaller
and smaller until it reaches a mesh which is too fine for it to pass through. Stack of sieves is mechanically shaken to promote the passage of solids. Fraction of material between pairs of Sieve size is determined by weighing the residue on each sieve. The result achieved will depend upon on the duration of the agitation and the manner of agitation.
Particle Volume Measurement:
(Range : 0.5-300 micrometer)
In this type the powder is suspended in
an electrolyte solution.This suspension is then made to flow
through a short insulated capillary section between
two electrodes
and the resistance of system is measured.
When the particles passes through capillary there is a momentary peak in the
resistance, the amplitude of the peak is proportional to the particle size.
Micromeritics' Applications
1.Release and dissolution.
2.Absorption and drug action.
3.Physical Stability.
4.Dose Uniformity.
Applications of Micromeritics is totaly a different topic. So I'll discuss it later in a new topic. Thanks for reading my article. I hope you like my work and visit my blog again for more updates. :)
Arqam Zahid
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