defects of tablets and its trouble shooting, defects related to industry point of view

1. DEFECTS OF TABLETS AND
ITS TROUBLE SHOOTING
BY,
M.SIMRANA FATHIMA
M.PHARMACY(PHARMACEUTIS)

2. CONTENT
 DEFECTS RELATED TO TABLETTING PROCESS
 Capping
 Laminating
 Cracking
 DEFECTS RELATED TO EXCIPIENT
 Chipping
 Sticking
 Picking
 binding

3.  DEFECTS RELATED TO MORE THAT ONE FACTOR
 Mottling
 DEFECTS RELATED TO MACHINE
 Double impression
 DEFECTS RELATED TO TABLET WEIGHT :SOURCE OF
VARIATION
 Product variation
 Machine condition
 Tooling condition

4.  PROBLEM &REMEDIES FOR TABLET COATING
 Blister
 Cratering
 Picking
 Pitting
 Blooming
 Blushing
 Colour variation
 Infilling
 Roughness/orange peel
 Cracking/splitting
 bridging

5.  OTHER DEFECTS INCLUDE
 Weight variation
 Punch variation
 Hardness variation
 Friability
 Hardness
 Poor flow
 Poor mixing
 Chipped edge
 Print defect
 Hair/fibre
 Black spot/stain
 Soft tablet
 Protracted disintegration

6. DEFECTS RELATED TO
TABLETTING PROCESS
LAMINATINGCAPPING CRACKING

7. CAUSES AND REMEDIES OF
CAPPING RELATED TO
FORMULATION
S.NO CAUSES REMEDIES
1. Large amount of fines in the granulation . Remove some or all fines through 100 to 200
mesh screen.
2. Too dry or very low moisture content (leading to loss of proper
binding action).
Moisten the granules suitably. Add
hygroscopic substance e.g.: sorbitol, methyl-
cellulose or PEG- 4000
3. Not thoroughly dried granules. . Dry the granules properly.
4. Insufficient amount of binder or improper binder. Increasing the amount of binder.
Adding dry binder such as pre-gelatinized
starch, gum acacia, powdered sorbitol, PVP,
hydrophilic silica or powdered sugar.
5. Insufficient or improper lubricant. Increase the amount of lubricant or change
the type of lubricant.
6. Granular mass too cold Compress at room temperature
7. Use of defective punches and dies Replacement of defective punches and dies.

8. CAPPING RELATED TO
MACHINE
S.NO CAUSES REMIDIES
1. Poorly finished dies Polish dies properly.
Investigate other steels or
other materials.
2. Deep concave punches or bevelled-edge faces of
punches.
Use flat punches.
3. Lower punch remains below the face of die
during ejection.
Make proper setting of lower
punch during ejection
4. Incorrect adjustment of sweep-off blade. Adjust sweep-off blade
correctly to facilitate proper
ejection
5. High turret speed Reduce speed of turret
(Increase dwell time)

9. LAMINATION RELATED TO
FORMULATION AND MACHINE
FORMULATION MACHINE
S.NO CAUSES REMEDIES CAUSES REMEDIES
1.
Oily or waxy materials in
granules
Modify mixing process.
Add adsorbent or absorbent.
Rapid relaxation of the
peripheral regions of a
tablet, on ejection from a
die.
Use tapered dies, i.e. upper
part of the die bore has an
outward taper of 3° to 5°.
2.
Too much of hydrophobic
lubricant e.g.:
Magnesium-stearate.
Use a less amount of
lubricant or change the type
of lubricant.
Rapid decompression
Use pre-compression step.
Reduce turret speed and reduce
the final compression pressure.
3.
Large amount of fines in
the granulation
Remove some or all fines
through 100 to 200 mesh
screen
4.
Too dry or very low
moisture content (leading
to loss of proper binding
action).
Moisten the granules
suitably. Add hygroscopic
substance e.g.: Sorbitol,
Methylcellulose or PEG-
4000

10. CRACKING RELATED TO
FORMULATION AND MACHINE
FORMULATION MACHINE
S.NO CAUSES REMEDIES CAUSES REMEDIES
1.
Large size of
granules.
Reduce granule size. Add
fines.
Tablet expands on
ejection due to air
entrapment
Use tapered die.
2. Too dry granules.
Moisten the granules
properly and add proper
amount of binder.
Deep concavities cause
cracking while removing
tablets
Use special take-off.
3. Tablets expand.
Improve granulation. Add
dry binders.
4. Granulation too cold.
Compress at room
temperature.

11. DEFECTS RELATED TO
EXCIPIENT
CHIPPING STICKING BINDING PICKING

12. CHIPPING RELATED TO
FORMULATION AND MACHINE
FORMULATION MACHINE
S.NO CAUSES REMEDIES CAUSES REMEDIES
1. Sticking on punch faces Dry the granules
properly or
increase
lubrication.
Groove of die
worn at
compression
point
Polish to open
end, reverse or
replace the die.
2. Too dry granules. Moisten the
granules
Barreled die
(center of the die
wider than ends)
Polish the die to
make it
cylindrical
3. Too much binding causes
chipping at bottom.
Optimize
binding, or use
dry binders.
Edge of punch
face turned
inside/inward
Polish the punch
edges.
4. Concavity too
deep to compress
properly
Reduce concavity
of punch faces.
Use flat punches.

13. STICKING RELATED TO
FORMULATION AND MACHINE
FORMULATION MACHINE
S.NO CAUSES REMEDIES CAUSES REMEDIES
1.
Granules not dried
properly.
Dry the granules properly.
Make moisture analysis to
determine limits.
Concavity too deep
for granulation.
Reduce concavity to
optimum.
2.
Too little or improper
lubrication.
Increase or change lubricant. Too little pressure. Increase pressure.
3. Too much binder
Reduce the amount of binder or
use a different type of binder.
Compressing too
fast.
Reduce speed.
4.
Hygroscopic granular
material.
Modify granulation and
compress under controlled
humidity.
5. Oily or way materials
Modify mixing process. Add an
absorbent.
6. Too soft or weak granules.
Optimize the amount of binder
and granulation technique.

14. PICKING RELATED TO
FORMULATION AND MACHINE
FORMULATION MACHINE
S.NO CAUSES REMEDIES CAUSES REMEDIES
1. Excessive moisture in granules.
Dry properly the granules,
determine optimum limit.
Rough or scratched punch
faces.
Polish faces to high luster.
2.
Too little or improper lubrication.
Increase lubrication; use colloidal
silica as a ‘polishing agent’, so that
material does not cling to punch
faces.
Embossing or engraving letters
on punch faces such as B, A,
O, R, P, Q, G.
Design lettering as large as
possible.
Plate the punch faces with
chromium to produce a smooth
and non-adherent face.
3. Low melting point substances, may soften
from the heat of compression and lead to
picking.
Add high melting-point materials.
Use high meting point lubricants.
Bevels or dividing lines too
deep.
Reduce depths and sharpness.
4. Low melting point medicament in high
concentration.
Refrigerate granules and the entire
tablet press.
Pressure applied is not enough;
too soft tablets.
Increase pressure to optimum.
5.
Too warm granules when compressing.
Compress at room temperature.
Cool sufficiently before
compression.
6. Too much amount of binder.
Reduce the amount of binder,
change the type or use dry binders.

15. BINDING RELATED TO
FORMULATION AND MACHINE
FORMULATION MACHINE
S.NO CAUSES REMEDIES CAUSES REMEDIES
1. Too moist granules and extrudes
around lower punch.
Dry the granules properly. Poorly finished dies. Polish the dies properly.
2.
Insufficient or improper lubricant.
Increase the amount of lubricant or
use a more effective lubricant.
Rough dies due to abrasion,
corrosion.
Investigate other steels or other
materials or modify granulation.
3.
Too coarse granules.
Reduce granular size, add more fines,
and increase the quantity of lubricant.
Undersized dies. Too little
clearance.
Rework to proper size.
Increase clearance.
4. Too hard granules for the lubricant
to be effective.
Modify granulation. Reduce granular
size.
Too much pressure in the tablet
press.
Reduce pressure. OR
Modify granulation.
5.
Granular material very abrasive
and cutting into dies.
If coarse granules, reduce its size.
Use wear-resistant dies.
6.
Granular material too warm, sticks
to the die.
Reduce temperature.
Increase clearance if it is extruding.

16. DEFECT RELATED TO MORE
THAN ONE FACTOR
DEFECT RELATED TO MACHINE
Double impression
 Involves only those punches, which have a monogram or other engraving on
them.
 If the upper punch is uncontrolled, it can rotate during the short travel to the final
compression stage and create a double impression.
 It is due to free rotation of punches which have some engraving or monogram on
the punch faces.
 During his free travel, the punch rotates and at this point, the punch may make a
new impression on the bottom of the tablet, resulting in 'Double Impression.
MOTTLING
unequal distribution of colour on a tablet, with light
or dark spots standing out in an otherwise uniform
surface.

17. CAUSES AND REMEDIES OF
MOTTLING
S.NO CAUSES REMEDIES
1.
A coloured drug used along with colourless or white-
coloured excipients.
Use appropriate colourants.
2.
A dye migrates to the surface of granulation while
drying.
Change the solvent system,
Change the binder,
Reduce drying temperature and
Use a smaller particle size.
3.
Improperly mixed dye, especially during ‘Direct
Compression’.
Mix properly and reduce size if it is of a larger size to prevent
segregation.
4. Improper mixing of a coloured binder solution.
Incorporate dry colour additive during powder blending step,
then add fine powdered adhesives such as acacia and tragacanth
and mix well and finally add granulating liquid.

18. CAUSES AND REMEDIES OF
DOUBLE IMPRESSION
S.NO CAUSES REMEDIES
1.
Free rotation of either upper punch
or lower punch during ejection of a
tablet.
-Use keying in tooling, i.e. inset a key alongside of
the punch, so that it fits the punch and prevents punch
rotation.
-Newer presses have anti-turning devices, which prevent
punch rotation.
2. Uncontrolled movement of
punches with engravings on them
Using anti-turning devices

19. TABLET WEIGHT-SOURCE OF
VARIATION
The tablet weights are mainly affected by following reasons :
PRODUCT VARIATION: This type of variation can be due to inconsistent
powder density and particle size distribution.Density can change on the press,
often because of overfilling of the die and re-circulation of the powder on the
tablet press, whereas particle size distribution may change when the product
becomes unblended during transfer or because of static electricity. This may also
change because the product cannot withstand the handling .

20. POWDER FLOW AND FEED-RATE
Various defects are related to powder flow and feed-rates stem
,therefore powder flow and feed-rates should be taken in account while
manufacturing of tablets.
MACHINE CONDITION
The problems caused by a tablet press that is poorly prepared or
operated are legion. The up and down motion under load on a new die
table should be within 0.003 inch of the setting. Care must be taken to
ensure that the pressure rolls and cams are in very good condition
TOOLING CONDITION
The punch working length should be taken in consideration. Working
length is an important factor in how punches affect tablet weight. New
tools are made to a tolerance of one-thousandth of an inch , the length
of each punch is correct and identical.

21. PROBLEM &REMEDIES FOR
TABLET COATING
S.NO PROBLEM DEFINITION CAUSES REMEDIES
1. BLISTERING It is local detachment of film from the substrate
forming blister.
Effect of
temperature on the
strength, elasticity
and adhesion of the
film.
Use mild drying condition.
2. CRATERING It is defect of film coating whereby volcanic-like
craters appears exposing the tablet surface
• Inefficient
drying.
• Higher rate of
application of
coating solution.
• Use efficient and optimum
drying conditions.
• Increase viscosity of coating
solution to decrease spray
application rate.
3. PICKING AND
STICKING
It is It is defect where isolated areas of film are
pulled away from the surface when the tablet
sticks together or to the pan and then detached
from one another or from the pan.
• Inefficient
drying.
• Higher rate of
application of
coating solution.
• Increase the inlet air
temperature
• Decrease the rate of
application of coating
solution.
4. PITTING It is defect whereby pits occur in the surface of a
tablet core without any visible disruption of the
film coating
Inappropriate
drying (inlet air )
temperature
Increase the drying (inlet air)
temperature

22. S.NO PROBLEM DEFINITION CAUSES REMEDIES
5. BLOOMING It is defect where coating
becomes dull immediately
or after prolonged storage
at high temperatures
High concentration and low
molecular weight of plasticizer.
Decrease plasticizer concentration
and increase molecular weight of
plasticizer
6. BLUSHING It is defect best described
as whitish specks or
haziness in the film.
• High coating temperature.
• Use of sorbitol in formulation
which causes largest fall in the
thermal gelation temperature
of the Hydroxy Propyl
Cellulose, Hydroxy Propyl
Methyl Cellulose, Methyl
Cellulose and Cellulose ethers.
• Decrease the drying air
temperature.
• Avoid use of sorbitol with
Hydroxy Propyl Cellulose,
Hydroxy Propyl Methyl
Cellulose, Methyl Cellulose and
Cellulose ethers.
7. COLOR
VARIATION
A defect which involves
variation in colour of the
film.
Improper mixing, uneven spray
pattern, insufficient coating,
migration of soluble dyes-
plasticizers and other additives
during drying.
Go for geometric mixing,
reformulation with different
plasticizers and additives or use
mild drying conditions.
8. ORANGE
PEEL
EFFECT/
ROUGHNES
S
It is surface defect
resulting in the film being
rough and non glossy.
Appearance is similar to
that of an orange.
Rapid Drying
High solution viscosity
Use mild drying conditions.
Decrease viscosity of solution.

23. S.NO PROBLEM DEFINITION CAUSES REMEDIES
9. BRIDGING This occurs when the coating fills in the
lettering or logo on the tablet
•High spray rate
•High viscosity of
solution,
•High percentage of
solids in the solution,
•Improper atomization
pressure.
•Reduce spray rate
•Reduce viscosity
•Reduce percentage of
solid
•Use proper atomization
pressure
10. CRACKIN
SPLITTING
It is defect in which the film either cracks
across the crown of the tablet (cracking)
or splits around the edges of the tablet
(Splitting).
Use of higher molecular
weight polymers or
polymeric blends.
Use lower molecular
weight polymers or
polymeric blends. Also
adjust plasticizer type
and concentration.
11. INFILLING It is defect that renders the intagliations
indistinctness.
Bubble or foam
formation because of air
spraying of a polymer
solution.
Add alcohol or use
spray nozzle capable of
finer atomization.
12. WEIGHT
VARIATION
Tablets will not have uniform weight. • poor flow of
granules.
• non-uniform
particle size
distribution of
granules.
• presence of
excessive fines.
• using proper
concentration of
lubricants and
glidants.
• by uniform size
distribution of
granules.
• decreasing the
proportion of
fines.

24. S.NO PROBLEMS DEFINITION CAUSES REMEDIES
13 POOR FLOW Improper flow of
powder from hopper to
die cavity leading to
incomplete filling of die
cavity.
• Particulate solids
moving under gravity
are subjected to
uneven pressure form
mass above and along
side.
• Hopper vibration/
mixing action leading
to segregation of
particles (large
particle on top &
small particle in
bottom)
• Arching/ Bridging/
Rat holing.
• Addition of glidant
(talc, colloidal silica)
• Using induced die
feeders
• Restricting the flow
of hopper
14. HARDNESS VARIATION Tablets do not have
uniform hardness.
• If volume & material
varies in die cavity.
• Distance between
punches varies
hardness will vary.
15 PUNCH VARIATION Differences in punch
lengths.
Lower punches of
unequal lengths changes
die cavity fill volume.
Using good punches with
uniform dimension and
die control program.

25. S.NO PROBLEMS DEFINITION CAUSES REMEDIES
16. CHIPPED EDGE Tablets having sharp edge,
elongated tablets are prone to
chipped edge.
Granules are subject
to high temperature
will improve chipped
surface (high drying).
17. HAIR/FIBRE HAIR/FIBRE As name itself
indicates some unwanted
particles/hair are appeared on tablet
surface.
• Not following SOP.
• Operator not
implementing
cGMP.
• Lack of attention
of operator
• Punches are
cleaned before
installing in their
respective places.
• Appropriate
cleaning
18. BLACK
SPOT/STAIN
Stains or spots will be appear on tablet
surface
High temperature
Improper cleaning of
punches
Maintains temperature
Proper cleaning
19. SOFT TABLET The tablets are susceptible to hydrolysis
will develop soft nature.
Lack of drying will
enhance the softness
Soft tablet will form
initiate/basis for sticking
or picking defects.
Application of low
compaction pressure.
The strength of bond is
weakened across
granules.
Granulation particles
will completely free from
moisture by keeping to
drying condition
properly.