PROBLEMS ASSOCIATED WITH TABLET MANUFACTURING

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PROBLEMS
ASSOCIATED WITH TABLET MANUFACTURING

Hello dear pharma bloggers

This is blog is aimed to cater the needs of those
pharma fresher graduates who have just completed their graduation and looking
to find their future in the phrama industry rather than higher education. If
you seem to have interest in the production department, or R & D you need
to have a keen knowledge of tablets.

Our team ASSIMILATORS have made a small attempt, I
hope you all would like this.

Please follow these links before reading this blog,
they include a brief note on introduction and tablet processing excipients.

http://www.pharmainfo.net/nandini/blog/introduction-tablets

http://www.pharmainfo.net/narmadha/blog/formulation-excipients-tablets

So to start with the
tabletting problems,

With the development of technology, the production process
had become more simplified and more mechanized; the complexity of a tablet
punching process has increased. But relatively reducing the problems associated
with the manufacturing process

In olden days tablets were initially punched on
small scale with hand operated machines, which suffered the problem of varied
strength and integrity,

http://www.labequipmentsindia.com/product/image/2252.jpg(1)hand
operated small scale production machine

(2)medium scale
production automated tablet punching machine

(3)
(large scale automated fast tablet punching machine.)

but now the
tablet punching machines are all mechanized, the mechanical feeding of feed
from the hopper into the die, electronic monitoring of the press, but still tablet
process problem still persist.

Tablet processing problems can be due to the problem
in the formulation or in the compression equipment, or both of them.

Thus we can classify the problems into following
three types(4,5,6):

1.
Problem
due to excipient:
chipping, picking, binding, sticking,
mottling,

2.
Problems
during process:
capping, lamination.

3.
Problem
due to machine:
double impression.

So at ever y step of the tablet manufacturing
process, utmost care should be taken to avoid defected tablet.

1) Problems due to excipient:

This
can arise due to the inaccurate addition of excipients or errors in the
granulation process. It includes: sticking, picking, binding, mottling.

O Picking:

o
Picking happens when a part of the
tablets gets sticks to the punch surface and gets eroded from the tablet
surface

o
This mostly happens with the upper
punch. And if this is left unchecked then this may lead to weight variation
too.

Sno

Cause

Remedy

1.

Due
to engraving or embossing on the upper punch

The
letters to be embossed should be in large size particularly on small punches,
or the size of the tablet be increased.

2.

Rough
punch surface

The
punch surface should be coated with chromium so as to get a smooth non
adherent face of punch.

3.

Sticky
surface of tablet

Colloidal
silica may be added in the formula as polishing agent to avoid sticking to
the punch

4.

Too
deep dividing lines

Reduce
the depth of the division.

5.

Excess
moisture.

Proper
drying of granules.

6.

Hot
granules while compression

The
granules are to be dried so that they do not stick.

7.

Excess
binder.

Reduce
the amount or change the binder so that the adhesive force is reduced and
more cohesive it becomes.

O Sticking:

o
It refers to the sticking of the tablet
material with the die walls.

o
Due to this sticking with the die walls,
additional force is required to eject the tablet form the die walls.

o
Sticking also causes production of
tablets with rough edges.

o
If this problem persists, then this can
cause chipping of the tablet.

o
It produced unusual stress on the cam
track and punch heads resulting in their damage!

Sno

Cause

Remedy

1.

Low
pressure

Increase
the pressure of punching

2.

Fast compression

Increase
the contact time by reducing the speed

3.

Greater
concavity of the punch

Reducethe
concavity of the punch to optimum level.

O Binding:

o
Binding is sticking of the tablet to the
die and does not eject properly out of the die.

o
It may be mainly due to lack of proper
lubricant or less quantity of lubricant, or may be due to excess moisture in
the tablet.

Sno

Cause

Remedy

1.

Less
or incorrect lubricant

Increase
the conc of lubricant or use appropriate lubricant

2.

High
moisture content of the tablet
material

The
granules are to be properly dried.

3.

Hard
granules reducing the effectiveness of lubricant

Reduce
the size of the granules by passing through 30 mesh so that increased surface
area can increase the chances of even binding of the lubricant.

4.

Worn
out dies walls

Polish
the dies properly

5.

Excess
pressure in the die

Reduce
the pressure with in the die.

O Chipping:

o
Chipping usually happens around the
tablet surface, small pieces are broken out or chipped out of the tablet.

o
It is mainly due to improper machine setting, like
ejection of the tablet.

Sno

Cause

Remedy

1.

Too
much drying

Moistane
the granule with an hygroscopic substance

2.

Worn
out punches

Polish
the punch surface to get a smooth finish

3.

Sticking
of the tablet material to the punch

Addition
of proper lubricant and properly dry the granules.

4.

Non
cylindrical dies with gap in the edges

Polish
the dies so that they become cylindrical shape.

O Mottling:

o
Mottling is uneven distribution of the
colour on the surface of the tablet, with dark and light patches on it.

o
It is mainly due to different
colouration of the excipient or the degradation product of the tablet is coloured.

(7)

Sno

Cause

Remedy

1.

A
dye may cause mottling when it migrates to the surface during the granulation
process

The
formulator is intended to change the solvent system, binder system, drying
temperature.

2.

When
coloured binder solution is not evenly distributed during mixing process

The
addition should in the sequence of First the powder colorant is added
followed by the binder like acacia or tragacanth, followed by the addition of
granulating liquid, and properly mixed.

3.

A
colored active ingredient used along with colourless excipients.

Addition
of appropriate colouring agent.

O Capping:

o
Capping is a complete or partial
separation of the upper or lower surface of the tablet horizontally, when the
tablet comes out of the die.

o
When the air is entrapped in between the
tablet material in a die, and when the material gets compressed between the two
punches, the air entrapped also gets compressed, but when the pressure is released
on the tablet I.e. when the two punched move apart and the tablet ejects out of
the die, the compressed sir expands and leads to capping.

Sno

Cause

Remedy

1.

Large
number of fines in the material

To
remove the excess of fines the granulation material should bee passed through
100 to 200 mesh.

2.

Improperly
dried granules

Dry
the granules properly.

3.

Inadequate
or improper binder

Increase
the quantity of binder or use and appropriate one.

4.

Compression
may not be firm due to cool temperature

Compress
the tablet material at higher temperature.

5.

Improper
setting of the lower punch, which
causes the sweep off blade to cut the surface

Correct
height of the lower punch should be adjusted so that the tablet is smoothly
ejected out.

O Lamination:

o
It is similar to capping but here the
tablet gets separated into layers.

o
It can once again occur due to the air
entrapment or due to the high speed of turret

Sno

Cause

Remedy

1.

Fast
decompression of the tablet

Precompression
step should be included in the process, so that the pressure at the final compression
is reduces.

2.

Granules
may contain oily or waxy material

Suitable
adsorbent or absorbent should be added.

(8)

(tablet capping and lamination)

O Double impression:

o
It is seen when the tablet punches have
engraving or monograms on it to be embossed on the tablet.

o
When the tablet material comes into the
die for the compression both the punches come in contact with the tablet
material and compress it, the next step is ejection of the tablet from the die,

o
During ejection process the lower punch
travels a small distance down and then comes up to give a gentle push to the
tablet, at this point when the lower punch moves down and comes up it moves in
a swirlling motion, due to the free rotation when it comes in contact with the
tablet for the second time to push it up it leaves another impression on the
tablet. Which is leads to double impression.

o
To avoid this key are to be used along
the sides of the punches, so that it prevents rotation of the punches.

This
blog is free from plagiarism.

Reference:

1. http://www.labequipmentsindia.com/product/image/2252.jpg

2. http://product-image.esuppliersindia.com/00431839/s/3/Tablet-Punching-Machine.jpg

3. http://www.gmpchina.net/image/p/gzpt1060.jpg

4. The
theory and practice of industrial pharmacy by Leon Lacman, Herbert A Lieberman,
Joseph L.Kang third edition, Varghese
publishing house page no -311-314

5. Pharmaceutical
Dosage Forms Tablets, Vol. 1, pg.no-
188-190

6. http://www.authorstream.com/Presentation/sabapathi-369361-problems-tablet-manufacturing-science-technology-ppt-powerpoint/

7. http://www.justice.gov/dea/programs/forensicsci/microgram/mg0206/mg0206_fig3.jpg

8. http://upload.wikimedia.org/wikipedia/en/2/27/Tabletfailure.jpg

raja_picta1023's picture
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Comments

vvummaneni's picture

1.Comment on the cause of defect on Tablet: a.If seen with rusting on it's Surface. b. Improper letters on the Tablet surface.

Vishnu Murthy Vummaneni

raja_picta1023's picture

hi vishnu thank you for going through my blog and for you comments. a) if rust is seen on the tablet it may be due to the improper polishing of the dies, lac of polish may lead to rusting and that must have got clinged to the tablet. b) double impression can be a reason for improper letters on the tablet. thank you!.

with regards K.Raja krishna TEAM ASSIMILATORS http://www.pharmainfo.net/rajapicta1023 email- rajapicta1023@gmail.com

vvummaneni's picture

1. How do you Optimize the Glidant and Lubricant concentration prior to production of Tablets in Pharma Industry. 2. State few common examples of drugs showing defect(s) due to excipients.

Vishnu Murthy Vummaneni