MICROMERITICS

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