• BLISTERING:- It is the detachment of film from the tablet substrate as the elasticity of surface film compromised.

Cause– generally occur due to higher temperature during various stages of coating.

• CHIPPING: It is generally an edge phenomena in which at the edge of tablet the surface film chipped off.

Cause- decrease in rotation speed of pan, poor coating solution.

• CRATERING: It is defect in which a defect in film coating leads to craters appearing exposing the tablet surface.

Cause- insufficient drying time, high volume of coating solution used.

• PICKING: It is defect where a surface film is pulled away from the surface when the tablet sticks together and then part due to being detached away from the core.

Cause- over wetting of tablets due to polymer solution, improper drying.

• PITTING: It is a defect in which deformation occur or pits formation occur in the surface of a tablet core without any visible disruption of the film coating.

Cause- it generally occurs when the temperature of core of the tablets generally higher than the melting points of material used in it.

• BLOOMING: It is defect where dullness in coating color of tablet occur after prolonged storage at high temperatures.

Cause- use of low molecular weight plasticizer.

• BLUSHING: It is defect in which whitish specks or haziness occur in the film.

Cause- occur due to the high coating temp. Leads to precipitation of polymers on surface.

• COLOR VARIATION: A defect which involves variation in color of the film.

Cause- poor mixing, uneven spray pattern, migration of dyes during drying etc.

• INFILLING– it refers to filling of intagliations (distinctive words or symbols on tablet surface)

Cause- due to accumulation or settling of foam in intagliations caused due to air spraying.

• ORANGE PEEL EFFECT: It is surface defect resulting in appearance of an orange peel having rough and non-glossy texture.

Cause- too high spray pressure, poor tablet composition, rapid drying etc.

• CRACKING/SPLITTING: It is defect in which the cracks in the films occur across the crown of the tablet (cracking) or splits around the edges of the tablet (Splitting).

Cause- occur when the internal stress of the film exceeds the tensile strength of film, use of high molecular weight polymers.
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Reference links
http://www.pharmainfo.net/tablet-ruling-dosage-form-years/problems-tablet-manufacture-and-related-remedies/tablet-coating-problems
https://www.lfatabletpresses.com/articles/different-tablet-coating-defects-and-remedies