The word Micromeritics refers to a discipline of science and technology that deals with studies related to the fundamental as well derived properties of particles. The knowledge and control of the size of particles is of importance in pharmacy and materials science.

1. PHYSICAL PHARMACY
Presented By: Simal Rizwan
Pharmacy 1st Proff
M.Islam College Of Pharmacy

2. • Introduction to Micromeritics
• Particle Size
• Particle Size Distribution
• Particle Number / Weight
• Average Particle Size
• Particle Volume

3.  The Science and Technology of small particles is
known as Micromeritics.
The term was created by J. M. DallaValle in his
book Micromeritics: the technology of fine
particles. It was derived from the Greek words
for small and part.

4.  A particle is a small, irregular 3D solid substance
 A particle is any unit of matter having defined physical
dimensions.
 The unit of particle size used in the micrometer (µm),
micron(µ) and equal to 10-6 m .

5.  Micromeritics includes a number of characteristics
including particle size, particle size distribution,particle
number , particle voulme , particle shape, angle of
repose, porosity, bulk volume, apparent density and
bulkiness (Properties) .
 A reduction in a powder’s particle size increases the number
of particles and the powder’s total surface area.
 Physical stability and pharmacologic response of
suspensions, emulsion and tablets depends on particle size.

6.  It is also important in flow properties and proper
mixing of granules and powders in tableting.
 Powders with different particle sizes have different
flow and packing properties which alter the volumes
of powder during each encapsulation or tablet
compression.
 Absorption capacity of a substance increases by
decrease in particle size.

7. Release and dissolution:
• Particle size and surface area influence the release of
a drug from a dosage form.
Example: (Tablet/Capsules)
Absorption and drug action:
• The higher the dissolution, the faster the absorption
and hence the quicker and greater the drug action.
• Particle size and surface area influence the drug
absorption and subsequently the therapeutic action.

8. Physical stability:
• The smaller the size of the particle, the better the
physical stability of the dosage form owing to the
decreased sedimentation.
For Example:
The solubility of Griseofulvin can be greatly increased by
particle size reduction.
Dose uniformity:
• The distribution of particles should be uniform in
terms of weight and volume.
Example: – Proper mixing of granules and powders

9. It is a notion introduced for comparing dimensions of solid
particles (fleck) , liquid particle (droplets) or gaseous particle
(bubbles).
 Physical properties of active pharmaceutical ingredients and
excipients largely depends on their particle size which are used to
formulate pharmaceutical dosage form . That is because particle size
and shape have profound impacts on each and every manufacturing
step.

10. • Colloidal Particles
• Particles Ecology
• Particles in granular matter
• Determine Grain size
Methods & Techniques
• Mesh Scale
• Optical granulometry
• Sieve analysis
• Soil Gradation

11. • One micrometer is equal to 10-3mm or 10-6m
• One milimicrometer is called nanometer (nm)
• One nanometer = 10-9 meter or 10-6 mm or 10-6μm.
The particle shape is playing a major role in particle size
distribution. The shape of a particle is not always regular
(symmetrical) and can be in asymmetrical or uneven.

12. Reduction of particle size can lead to a decrease in rate
of dissolution.
As an example, theophylline tablet containing 30-50
μm particle size showed faster dissolution than that of
10 μm.
 In case of asymmetrical particle
◦ Using equivalent spherical diameters (which relates
size of asymmetric particle to a sphere with same surface
area (surface diameter), volume (volume diameter) or
density (Stokes diameter).

14. Most effective device:
Inlie Imaging Device Like SOPAT
Thus used in industries i.e chemical food , forestry and
agriulture etc..
Benefits of Particle Size:
Help in effectiveness of a Drug
Crushing Material
Increasing the exposure of poorly soluble Drugs

15. In powder the particles of varying size, shape and
number exist, therefore to estimate the size
range and number or weight fraction of each
particle size is necessary and is called particle
size distribution.

16.  When the number or weight of particles lying within
a certain size range is plotted against the size range or
mean particle size, a so-called frequency
distribution curve is obtained.
 In the next slide particle-size distribution graph is
shown and from it we can calculate an average
particle size for the sample.

18.  Particle size growth may be monitored during
operations such as granulation or crystallization.
Importance
o Particle size of the cocoa powder used in chocolate affects color
and flavor. The size and shape of the glass beads used in highway
paint impacts reflectivity. Cement particle size influences
hydration rate & strength.

19. o In the pharmaceutical industry the size of active
ingredients influences critical characteristics including
content uniformity, dissolution and absorption rates.
CEMENT COCOA POWDER
 It is therefore necessary to know not only the size of certain particles
but also how many particles of same size exist in sample.

22. Product quality research institute suggested that use of
image analysis for particular size distribution will give a
Number-Weight Distribution.
 This is important because it is possible to have two
samples with the same average weight but different
distributions.

23. Granular material by allowing
the material to pass through
a series of sieves of
progressively smaller mesh
size and weighing the
amount of material that
is stopped by each sieve
as a fraction of the whole mass.

25.  A significant expression in particle technology is the number
of particles per unit weight N, which is expressed on terms of
dⱱἡ.
 For Example:
Three particles are 1µm, three are 2µm, and three are 3µm in
size (diameter). Building a number distribution for these
particles will generate the result shown in Figure ,where each
particle size accounts for one third of the total.

27.  The average particle size may be obtained by
observing the number of particles in each size range:
Particle size = ∑nd/∑n
 Certain modifications can be made to take into account
the surface and volume of particles.
Edmundso n Eq. : dmean= (∑ndp+f /∑nf)1/p
◦ n is no. of particles in each size range, d is the diameter
(mid value), p is the index related to size of individual
particle and f is the frequency index.

28.  d raised to the power p=1 gives paticle length; p=2 gives surface and
p=3 gives the volume.
 P= positive then mean is arithmatic; p= zero then mean is
geometric and if p=negative then mean is harmonic.
 Frequency (certain size range)= ndf . f equal to 0, 1, 2, or 3
then the size distribution is expressed in total number,
length, surface or volume of particles respectively.
• f =1 express size distribution in length
• f = 2 express size distribution in surface
• f = 3 express size distribution in volume

30. Volume-based particle size equals the diameter of the
sphere that has the same volume as a given particle.
Typically used in sieve analysis, as shape hypothesis
(sieve's mesh size as the sphere diameter).
 Most of instruments called "particle size analyzers"
apparently measure particle size distribution based on
the volume standard.

31.  Figure 1 shows a population where there are 13 beans in each
of three size classes, equal on a number basis. The same
figure shows these beans placed in volumetric cylinders where
It becomes apparent that the larger beans represent a much
larger total volume than the smaller ones.

32. Figure 2 shows a population of beans where it may not be
intuitively obvious, but there is an equal volume of each size,
despite the wide range of numbers present.
 It becomes apparent that when the beans are placed in
volumetric cylinders that each volumes are equal.