A HELPFUL PRESENTATION FOR TABLET COATING

1. Prepared By:
BHANU BISWAS
M.Pharm(Quality Assurance)
Maharishi Markandeswar(Deemed To Be
University)
TABLET COATING
18 April 20181

2.  A tablet coating is a process of
covering over a tablet which is used
to mask the taste, make it easier to
swallow, or protect the active
medication inside.
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3. PURPOSE OF COATING
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 Protection against light, air and moisture.
 Protecting API against digestive fluids.
 Better identification of tablets.
 Avoid side-effects.
 Provides a delayed release of medication.

4. TYPES OF COATING
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There are mainly 3 types of coating
 Sugar Coating
 Film Coating
 Enteric Coating

5. 1. SUGAR COATING
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 This involves application of sugar (sucrose)
based coating solution to the tablets.
 It is carried out in coating pans having variable
capacities and mounted at an angle of 40º
 The coating is water soluble and dissolves after
swallowing.

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 The sugar coating involves following steps:
i. Sealing iv. Finishing
ii. Sub coating v. Polishing
iii. Syruping

7. SEALING
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 The tablet core must be sealed, dried and free
from any residual solvents.
 It prevents moisture penetration into the tablet
core.
 Seal coating agents are Oleic acids, PEG-4000,
Alcohol, Methylene glycol.

8. SUB COATING
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 It is actual starting of coating process and acts as the
foundation for smoothening and polishing.
 Sub coating is applied to build up tablet size and to
form uniform edges.
 It increase the tablet weight from 50-100%
 Eg: Gum acacia, Corn syrup, Gelatine.

9. SYRUPING
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 It is done to cover the imperfections in the
tablet surface that is caused during sub coating
step.
 Eg: Colorant, Cane sugar powders, Calcium
carbonate, Corn starch.

10. POLISHING
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 The desired lustre to the tablet is obtained by
polishing.
 Tablets are polished in standard coating pans
by application of bees wax, paraffin wax or
warm solution of waxes in suitable volatile
solvents.

11. 2. FILM COATING
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 This technique is more used as compared to sugar
coating.
 In this process there is deposition of a thin film of
polymer surrounding the tablet core.
 The film formed is very thin and it gives the
tablet a less weight and small size.
 Eg: HPMC (Hydroxy Propyl Methyle Cellulose),
EC (Ethyle Cellulose), HPC (Hydroxy Propyl
Cellulose), etc.

12. 3. ENTERIC COATING
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 Enteric coated tablets have delayed release
features.
 They are designed to pass unchanged through
the stomach to the intestines where the tablets
disintegrates and allow drug dissolution and
absorption.
 Eg: Omeprazole, Aspirin,etc

13. MODE OF ACTION
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15. 1. Conventional Pan Coater
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 They have circular metal pan mounted at 40º
 They are of 8-60 inch diameter.
 They are rotated on its horizontal axis by a
motor.

16. PELLIGRINI COATING PAN
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 Heated air is supplied by inlet air supply.
 Coating solutions are applied to tablets by
spraying the material on the rotating tablet bed.
 It produces even distribution of coating
solutions or suspensions.
 The inlet air are exhausted by means of ducts
through the front of the pan.

18. IMMERSION TUBE COATING PAN
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 It consists of long tube with a spray nozzle at
its tip.
 Hot air as well as solution gets delivered
through this tube into the tablet bed.
 Drying air flows upward and exhausted
through duct.
 This is used for both sugar coating as well as
film coating tablets.

20. 2. PERFORATED PAN SYSTEM
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 It is perforated or partially perforated drum.
 The coating solutions are applied to the surface
of the rotating bed of tablets through spray
nozzels which are present inside drum.
 Perforated pan coaters are efficient drying
systems with high coating capacity.

21. ACCELA-COTA PAN
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 It consists of mixing blades.
 Dry air is directed into the pan to the tablet bed.
 The spray gun sprays the coating solution
evenly.
 Exhausted air moves out of the pan through the
suction shoe.

23. DRIA COATER PAN
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 The dry air enters through hollow perforated
ribs located inside the periphery of the drums.
 The spray evenly sprays the coating solution as
the coating pan rotates.
 The drying air passes up through exhaust which
is present in the back of the pan.

25. 3. FLUIDIZED BED SYSTEM
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 The movement of the tablets is upward through
the centre of the chamber.
 Then they fall down towards the chamber wall,
re-enters the air stream at the bottom of the
chamber.
 Coating solutions are applied from a spray
nozzle which is located either at the top or
bottom of the chamber.