This presentation discusses roller compactors, which are used to press powders into solid compacts like flakes or sheets. Key factors that affect roller compaction include compaction pressure, feeding screw speed, and roll speed. A roller compactor generally consists of a feeding system, compaction unit with counter-rotating rolls, and a size reduction unit. It works by applying force between the rolls to compact powders into a ribbon. Roller compactors can have either a fixed or floating gap between rolls. The major advantages include avoiding solvents, suitability for heat-sensitive compounds, and producing porous tablets for improved dissolution. Applications in pharmaceuticals include excipient production, drug compaction, herbal extract granulation, and

1. Welcome to My Presentation
Presentation Topic: Roller Compactor
MD. RASHEDUZZAMAN JONY

2. Roller Compactor
Roller Compactors are used to force fine powders between two counter rotating rolls
and presses the raw materials into a solid compact (flakes, sheets, strips). Roller
compactors are also called dry granulators.
Factors affecting Roller Compaction;
• Compaction Pressure (compaction force per cm of roll width)
• Speed of feeding screws
• Roll Speed

3. Structure of a general Roller Compactor

4. Principle of Roller Compactor
A roller compactor generally consists of three major units.
• A feeding system which converts the powder to the compaction area between the rolls.
• A compaction unit where powder is compacted between two counter rotating rolls to a ribbon by
applying a force.
• A size reduction unit for milling the ribbons to the desired particle size.
The most important parameter in the dry granulation process is the force applied on the
powder compacted between two rolls. The applied force is expressed in kN/cm, being the
force per cm roll width.

5. How a Roller Compactor works with it’s different parts

6. Types of Roller Compactor
Roller compactors can be divided into two categories;
One is equipped with a fixed gap and the other one with a floating gap. Both consist of the three major
units as explained above but differ in the way in which the smallest gap between the rolls is realized.
• When a fixed gap is installed, the amount of powder drawn in into the compaction area between the rolls is
inconsistent, which results in different forces applied to the powder bed. Like in slugging, this will cause
large fluctuations in the ribbon and granulate properties.
• In floating gap the distance between the rolls change according to the amount of powder provided. The
force applied to the powder remains constant. This ensures that property fluctuations in the granules are
reduced to a minimum.

7. Advantages
• A major advantage of dry granulation over wet granulation is the absence of water or
any organic solvents. Therefore, this methodology is especially attractive for drugs
which are moisture or heat sensitive.
• This is suitable for compounds that either have a low melting point or degrade rapidly
during heating as the method does not involve any drying step.
• Roll compaction results in granules that form porous tablets thus allowing water to
penetrate more easily into the tablet. This leads to improved disintegration behavior
of tablets.
• In addition, this process is environmentally friendly. Also the roll compaction
technique provides an efficient and easily automated process

8. • Low operational cost.
• Dust problems are minimized or avoided and the die filling during tableting is improved.
• The capping of tablets might also be reduced.
• Roll compaction/dry granulation can be used, if the drug or the excipient is poorly flowing or
sensitive to heat or moisture.
• It can also be used for densification of powders prior to encapsulation.

9. Disadvantages
• One of the disadvantages of roll compaction is a phenomenon called ‘loss of rework ability’.
Tablets made by roll compaction often show inferior tensile strength compared to tablets
prepared by wet granulation or direct compaction. Minimum compaction force should be used,
as well as a smaller particle size of starting powder.
• A second disadvantage of roll compaction is the production of non-compacted powder. Because
no liquid binder is used, high amounts of fines remain and less product yield is obtained versus
wet granulation.

10. Applications in Pharmaceutical Industry
• Preparation of directly compressible excipients: An ideal excipient for direct
compression is a material with good flow ability and compactibility. In many cases, an
agglomeration is required to produce a directly compressible excipient.
• Compaction of drugs and drug formulations: Some drugs have low and
inconsistent bulk and tap densities accompanied with very fine and inconsistent
particle sizes. If the material also exhibits poor flow properties and poor
compactibility, roll compaction might be used to overcome the raw material
difficulties.

11. • Granulation of herbal dry extracts: Herbal dry extracts often possess a
considerable hygroscopicity due to their hydrophilic components like sugars or
organic acids. Furthermore, extracts often show poor flow and compression
properties making a compaction/ granulation step necessary prior to tableting.
• Immediate release formulations and enhanced dissolution
• Controlled release formulations

12. Success is not that what we always see
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