Amity Institute of Pharmacy
Amity Institute of Pharmacy
B.Pharm 5th semester
Subject : Industrial pharmacy [BP 502T]
TOPIC – Tablet coating defects
PRINCE KUMAR ’64’
B.Pharm 5th sem student
Amity institute of pharmacy
Amity Institute of Pharmacy
Tablet coating is the process of applying a coating
material to the surface of a tablet to enhance its
properties, such as taste, stability, and ease of
swallowing, as well as to protect it from the gastric
environment and modify its release properties.
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why to coat a tablet ?
Improving taste, odor, and color of the drug.
Improving ease of swallowing by the patient.
Improving product stability.
To protect against the gastric environment.
To improve mechanical resistance of the dosage form.
Modifying release properties.
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[1].BLISTERING
➢ It is a local detachment of film from the
substrate forming blister.
➢ Reason -- This is because of the gas Penetration
inside/ underneath the film. It may be due to overheating
during spraying.
➢ Remedy--Use mild heating or temperature conditions
during the Coating process.
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[2].BLOOMING
➢ The fading / dulling of a tablet after
prolonged storage of tablet.
➢ Reason -- High concentration of plasticizer
➢ Remedy-- Use a lower concentration of
plasticizer. 6
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[3].Cratering
➢ In this defect , a bowl shaped craters may
appear on the tablet surface.
➢ Reason -- Penetration of coating solution
at the surface of the tablet.
➢ Remedy -- Decrease the spray rate and use
optimum drying conditions
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[4].Cracking/Splitting
➢ It is a coating defect in which the film either
cracks across the crown of the tablet
(cracking) or splits around the edges of the
tablet (Splitting).
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Reason – When the internal
tension of the film is beyond its
tensile strength, cracking occurs.
Remedy –Try to add lower
molecular weight polymers or a
polymeric mixture
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5.Sticking and Picking
➢ In this defect tablet film sticks to the pan and
some part pulled away from surface.
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Reason --
Due to over wetting of tablets by coating solution
spray rate is too high
Pan speed is too low.
➢ Remedy –
Decrease volume of coating solution
Reduce spray rate,
Increase pan speed.
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6. Roughness (“Orange peel”)
➢ The rough surface of the tablet gives it the
look of an “Orange Peel,” and it may also
have a dull instead of a shiny finish
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Reason -- Rapid Drying,
Too high coating suspension
viscosity
Remedy -- Use mild drying
conditions,
Reduce the viscosity coating
suspension
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7.Twinning
➢ It is a coating defect where tablets stick
together especially when two tablets
stick together
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Reason -- Excessively tacky
coating formulation, Insufficient
drying.
Remedy -- Use coating
formulation which is less
tacky, Use optimum drying
conditions.
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8. MOTTLING
➢ Mottling defect in tablets refers to the.
uneven distribution or appearance of
color on the surface of oral solid dosage
form tablets.
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Reason -- It can occur due to inadequate
mixing, variations in particle size or
density, incompatible excipients, poor
granulation techniques, or environmental
factors.
Remedy — Do proper mixing, take the
particles of same size and density, use
compatible excipients , use appropriate
colorants.
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