Multi station rotary presses
Prof. R. Shanthini
22 Oct 2012
Source: http://vivekkivani.blogspot.com/

Although tablet compressing machinery has
undergone numerous mechanical modifications
over the years, the compaction of materials
between a pair of moving punches within a
stationary die has remained unchanged

The principle modification from earlier equipment
has been an increase in production rate which is
regulated by
 Number
of tooling sets
 Number of compression stations
 Rotational
Prof. R. Shanthini
22 Oct 2012
speed of the press
Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of
Pharmaceutical Sciences, Khon Kaen University

Special adaptations of tablet machines allow for
the compression of layered tablets and coated
tablets

A device that chills the compression
components to allow for the compression of
low-melting point substances such as waxes i.e.
suppositories
Prof. R. Shanthini
22 Oct 2012
Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of
Pharmaceutical Sciences, Khon Kaen University
Compression
The ultimate test of a tablet formulation and
granulation process is whether the granulation can
be compressed on a high-speed tablet press.
During compression, the tablet press performs the
following functions:
Filling of empty die cavity with granulation.
2. Precompression of granulation (optional).
3. Compression of granules.
4. Ejection of the tablet from the die cavity and take-off of
compressed tablet.
1.
Prof. R. Shanthini
22 Oct 2012
When evaluating the compression characteristics
of a particular formulation, prolonged trial runs at
press speeds equal to that to be used in normal
production should be tried.
Only then are potential problems such as sticking
to the punch surface, tablet hardness, capping,
and weight variation detected.
High-speed tablet compression depends on the
ability of the press to interact with granulation.
Prof. R. Shanthini
22 Oct 2012
Following are the parameters to be considered
while choosing speed of press.
Granulation feed rate.
2. Delivery system should not change the particle size
distribution.
3. System should not cause segregation of coarse and fine
particles, nor it should induce static charges.
1.
Prof. R. Shanthini
22 Oct 2012
The die feed system must be able to fill the die
cavities adequately in the short period of time
that the die is passing under the feed frame.
The smaller the tablet , the more difficult it is to
get a uniform fill a high press speeds.
For high-speed machines, induced die feed
systems is necessary.
These are available with a variety of feed
paddles and with variable speed capabilities.
So that optimum feed for every granulation can
be obtained.
Prof. R. Shanthini
22 Oct 2012
After the die cavities are filled ,the excess is
removed by the feed frame to the center of the die
table.
Compression of the granulation usually occurs as
a single event as the heads of the punches pass
over the lower and under the upper pressure
rollers.
This cause the punches to the penetrate the die to
a preset depth, compacting the granulation to the
thickness of the gap set between the punches.
Prof. R. Shanthini
22 Oct 2012
The rapidity and dwell time in between this press
event occurs is determined by the speed at which
the press is rotating and by the size of
compression rollers.
Larger the compressions roller, the more gradually
compression force is applied and released.
Prof. R. Shanthini
22 Oct 2012
Slowing down the press speed or using larger
compression rollers can often reduce capping in
a formulation.
The final event is ejection of compressed tablets
from die cavity.
During compression, the granulation is
compacted to form tablet, bonds within
compressible material must be formed which
results in sticking.
Prof. R. Shanthini
22 Oct 2012
High level of lubricant or over blending can result
in a soft tablet, decrease in wettability of the
powder and an extension of the dissolution time.
Binding to die walls can also be overcome by
designing the die to be 0.001 to 0.005 inch wider
at the upper portion than at the center in order to
relieve pressure during ejection.
Prof. R. Shanthini
22 Oct 2012
DIFFERENT PUNCHES & DIES
Prof. R. Shanthini
22 Oct 2012
Tableting methods (already seen)

Dry methods
 Direct
 Dry

compression
granulation
Wet methods
 Wet
Prof. R. Shanthini
22 Oct 2012
granulation
Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of
Pharmaceutical Sciences, Khon Kaen University
WET GRANULATION
DRY GRANULATION
DIRECT
COMPRESSION
1. Milling and mixing of drugs and excipients
2. Preparation of binder
solution
2. Compression into slugs
or roll compaction
3. Wet massing by addition of
binder solution or
granulating solvent
3. Milling and screening of
slugs and compacted
powder
4. Screening of wet mass
4. Mixing with lubricant and
disintegrant
5. Drying of the wet granules
5. Compression of tablet
6. Screening of dry granules
7. Blending with lubricant and
disintegrant to produce
“running powder”
8. Compression of tablet
Prof. R. Shanthini
22 Oct 2012
2. Compression of
tablet
Direct compression

Tablets are compressed directly from
powder blends of the active ingredient and
suitable excipients

No pretreatment of the powder blends by
wet or dry granulation procedures is
necessary
Prof. R. Shanthini
22 Oct 2012
Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of
Pharmaceutical Sciences, Khon Kaen University
Advantages
 Economy

Machine: fewer manufacturing steps and pieces of
equipment
Labor: reduce labor costs
 Less process validation
 Lower consumption of power

Prof. R. Shanthini
22 Oct 2012
Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of
Pharmaceutical Sciences, Khon Kaen University
Advantages (contd.)
 Elimination
of granulation process
Heat (wet granulation)
 Moisture (wet granulation)

High pressure (dry granulation)
 Processing without the need for moisture and heat
which is inherent in most wet granulation
procedures


Avoidance of high compaction pressures involves
in producing tablets by slugging or roll compaction
Prof. R. Shanthini
22 Oct 2012
Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of
Pharmaceutical Sciences, Khon Kaen University
Advantages (contd.)
 Elimination
of variabilities in wet granulation
processing
Viscosity of the granulating solution (depend on its
temperature),
 How long it has been prepared,
 Rate of binder addition and kneading can affect the
properties of the granules formed


The granulating solution, the type and length of mixing
and the method and rate of wet and dry screening can
change the density and particle size of the granules,
which can have a major effect on fill weight and
compaction qualities
Prof. R. Shanthini
22 Oct 2012
Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of
Pharmaceutical Sciences, Khon Kaen University
Advantages (contd.)
 Type


and rate of drying
can lead to unblending as soluble active ingredients
migrate to the surfaces of the drying granules
Less unit processes incorporated in
production means less chances of batch-tobatch variation are compounded
Prof. R. Shanthini
22 Oct 2012
Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of
Pharmaceutical Sciences, Khon Kaen University
Direct compression fillers

Common materials that have been
modified in the chemical manufacturing
process to improve fluidity and
compressibility
Prof. R. Shanthini
22 Oct 2012
Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of
Pharmaceutical Sciences, Khon Kaen University
Soluble fillers







Spray dried lactose (good flowability; less compressibility)
Fast-Flo lactose (much more compressible and highly
fluid)
Tabletose: aggromerate form of lactose (More
compressible than spray dried but less compressible than
Fast Flo lactose)
Di-Pac: cocrystallization of 97% sucrose and 3% modified
dextrin
Sorbitol
Maltodextrin (Highly compressible; completely soluble )
And more….
Prof. R. Shanthini
22 Oct 2012
Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of
Pharmaceutical Sciences, Khon Kaen University
Insoluble fillers




Starch 1500: intact starch grains and ruptured starch
grains that have been partially hydrolyzed and
subsequently agglomerated
Era-Tab: spray-dried rice starch (good fluidity;
compressibility depends on moisture)
Avicel: microcrystalline cellulose (the most important
tablet excipient developed in modern times; most
compressible)
Dicalcium phosphate (Emcompress or DiTab)
Prof. R. Shanthini
22 Oct 2012
Source: Assoc. Prof. Dr. Jomjai Peerapattana, Faculty of
Pharmaceutical Sciences, Khon Kaen University