This document discusses various micronization techniques used to reduce drug particle sizes to the micron range and enhance bioavailability. It describes 9 common techniques: fluid energy mill, ball mill, edge runner mill, rotary cutter mill, end runner mill, roller mill, hammer mill, mortar and pestle, and colloid mill. Each technique is explained in terms of its working principles and mechanisms of size reduction such as attrition, impact, shearing, compression, and cutting. The overall aim of micronization is to increase drug dissolution and absorption by increasing surface area through reducing particle size.

1. MICRONIZATION TECHNIQUES
Presented By..
Mr. Wagh Pankaj N.
M.Pharm.(1st Sem)
Department Of Pharmaceutics
R.C.Patel Institute Of Pharmaceutical Education and Research, Shirpur.
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2. CONTENTS
 Introduction
 Micronization Techniques
a) Fluid energy mill
b) Ball mill
c) Edge runner mill
d) Rotary cutter mill
e) End runner mill
f) Roller mill
g) Hammer mill
h) Mortar and Pestle
i) Colloid mill
 Conclusion
 References 2

3. 3
INTRODUCTION:
The process involve reducing the size of the
solid drug particle to 1 to 10 micron commonly
by use of air attrition method (fluid energy mill).
The process is also called as micro-milling.
Example of drug whose bioavailability have
been increased by micronization include
griseofulvin & several steroidal and sulpha
drugs.

4. MICRONIZATION TECHNIQUES:
1. FLUID ENERGY MILL OR JET MIL
2. BALL MILL OR PEBBLE MILL
3. EDGE RUNNER MILL
4. ROTARY CUTTER MILL
5. END RUNNER MILL
6. ROLLER MILL
7. HAMMER MILL
8. MORTOR & PASTLE
9. COLLOID MILL
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NAME OF MILL ACTION OF MILL
Fluid Energy Mill Attrition & Impact
Ball Mill Attrition & Impact
Edge Runner Mill Crushing & Shearing
Rotary Cutter Mill Cutting
End Runner Mill Crushing & Shearing
Roller Mill Compression
Hammer Mill Impact
Colloid Mill Shearing
Table- Types of mill and their
actions

6. Principle:
Fluid energy mill operates on the principle of impact and
attrition the feed stock is suspended with in a high velocity air
stream.
1) Fluid Energy Mill:
Fig: Fluid energy mill
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7. Working:
Powder is introduced through the inlet of venturi.
Air introduce through the grinding nozzles transport the
powder in the circular track of the mill. The turbulent
stream of air the particles colloids with each other and
break. Particles are carried out to outlet and the coarse
particle undergo recirculation.
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Uses-
Reduce particle size of most of drugs such as
antibiotics and vitamins.
Advantages-
1) Heat labile substance can be milled.
Ex. Sulphonamide, Vitamins and antibiotics.
2) It is rapid & efficient method for reducing powder
30 mm or less.
Disadvantage-
1) Not suitable for soft, tacky & fibrous material.

9. Principle:
The ball mill works on the impact between the rapidly
moving ball and the powder material, both enclosed in a
hollow cylinder. Thus, in the ball mill, impact or attrition or
both are responsible for the size reduction.
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2) Ball Mill:
fig: Ball mill

10. Working:
The drug is filled into cylinder 60% of the volume.
A fixed number of ball introduced and cylinder is close.
The mill is allowed to rotate on its longitudinal axis.
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11. Uses :
1) Milling of hard and abrasive material with particle size of
5mm or less.
2) Ball mill at low speed is used for milling dyes, pigment and
insecticides.
Advantages:
1) It can produce very fine powder.
2) Used for batch operation.
3) Suitable for both wet and dry grinding processes.
Disadvantages:
1) Noisy machine.
2) Not suitable for soft, tacky & fibrous material.
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12. Principle:
Size reduction done by compression due to heavy weight of
stone.
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Fig : Edge Runner Mill
3) Edge Runner Mill:

13. Uses:
1. For grinding tough material to fine powder.
2. Use for plant based product.
Advantage:
1. Not require attention during operation.
Disadvantages:
1. Time consuming and Energy consuming.
2. Not use for sticky material.
Working:
Material to be ground is placed on the bed at the same
time travel around the shallow stone bed so the size
reduction is achieved by sharing as well as crushing.
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14. Principle:
In the cutter mill, size reduction involves successive cutting or
shearing the feed materials with the help of sharp knives.
Fig: Rotary cutter mill 14
4) Rotary Cutter Mill:

15. • Rotor disc rotate at 200-900 revolution per min.
• Feed material loaded through hopper.
• Material is cut between rotating & stationary knives in
small pieces, therefore particle pass through the screen
product is collected into receiver.
Working:
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16. Uses:
1. Size reduction of tough and fibrous material
2. Manufacture of rubber, plastics, recycling of
waste paper and plastic materials
3. Medicinal plants, plant parts and animal tissue
are converted into small parts.
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17. Principle:
Size reduction is done by crushing due to heavy weight of
steel pestle. Shearing stress is also involved during movement of
mortar and pestle.
Fig:- End runner mill 17
5) End runner mill:

18. 18
Working:
The material to be ground is placed in the mortar. The
mortar revolves at a high speed. The revolving mortar causes
the pestle to revolve during this process, size reduction is
achieved.
Uses:
Use for fine grinding.
Disadvantages:
Not suitable for unbroken or slightly broken condition
of drug.

19. Principle:
The material is crushed (compressed) by the application
of stress. The stress is applied by rotator wheels, rollers.
Fig: Roller mill.
Feed
Hopper
Rollers
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6) Roller mill:

20. Working:
The rollers are allowed to rotate. The material is feed into
hopper through gap between two rollers by applying high
pressure material is crushed.
Uses:
Roller mill is used for crushing and cracking of seed before
extraction of fixed oils and also used to crush soft tissue to help
in the penetration of solvent during extraction process.
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21. Principle:
The hammer mill operates on the principle of impact between
rapidly moving hammer mounted on a rotor and the powder
material.
Fig: Hammer mill 21
7) Hammer mill:

22. Working:
The hammers are allowed to be in continuous
motion(8000-15000 rpm) the feed material is placed into the
hopper, whiles hammers are in continuous motion.
Uses:
 Particle size obtained from 10-400mm.
 Also used to mill dry, wet and filter press cakes materials.
Advantages:
 Easy to setup and clean up.
 Occupies small space.
Disadvantages:
• Heat buildup during milling is more, therefore, product
degradation is possible.
• Not suitable for milling of soft, tacky and fibrous materials.
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23.  This is the classical and the simplest equipment for grinding.
 It is work on application of attrition and pressure.
 In this equipment both mortar and pestle are rotating.
 This equipment cannot be provided with a sieve for. continuous
removal of fines.
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8) Mortar and Pestle:

24. Principle:
Colloid mill consist of 2 steel disc having very small clearance
between them. One disc is rotating, while the other one is
stationary.
Fig:-Colloid Mill
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9) Colloid Mill:

25. Working:
Suspension and emulsion are placed in hopper. The solid
are mixed with the liquid vehicle before introduce into colloid
mill Rotor is moved 3000 to 20000 rpm. The dispersion flow
down and adher to the rotor.
Uses:
Colloidal dispersion, suspension, emulsion, and ointment.
Advantage:
Production of sterile product.
Disadvantage:
Not useful to dry milling.
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Conclusion:
Micronization is one of the technique for
reducing particle size to enhancement of
bioavailability of drug.
So we conclude that by reducing particle size there is
increase in surface area, so ultimately dissolution rate is
enhanced and thereby bioavailability can be increased by
micronization techniques.

27.  Aulton , Aulton Pharmaceutics, The Science of Dosage form Design, 2nd Edition
(2002), Churchill Livingstone; pp.166-173.
 Subrahmanyam C.V.S, Pharmaceutical Engineering Principles and Practices,
1stEdition (2001), Vallabh Prakashan; pp.148-164.
 Brahmankar D.M & Jaiswal S.B, Biopharmaceutics and Pharmacokinetics ,2nd
Edition (2009),Vallabh Prakashan; pp.348-349.
References:
27

28. Cont....
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 Cooper and Gunn's, Tutorial Pharmacy, 6th Edition (2005),CBS Publication,
New Delhi; pp.183-191
 Kamath.A. Method Of Size Reduction and Factor Affecting Size Reduction In
Pharmaceutics: A review.2013;4(8):57-64.
 Joshi Jalay T. Journal of Pharmaceutical Science and Technology: A review on
micronization techniques. 2011;3(7): 651-681.

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