Transcript Tablet Coating

Tablet Coating
Why coat tablets?
Types of coatings
 sugar coating
 film coating
 press coating (compression coating)
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Sugar Coating
stages involved:
 sealing of tablet core
 subcoating
 smoothing
 colouring
 polishing
 printing
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Film Coating
Involves spraying a solution of polymer + pigments +
plasticizers onto a rotated, mixed tablet bed to form a
thin, uniform film on tablet surface.
materials
 polymers
 solvents
 plasticizers
 colorants
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Coating Process
coating pans
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The Coating Process
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Film Formation
latex particles dispersed
in aqueous phase
formation of thin film with
water evaporation through film
continuous film
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Air Flow
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Coating Process
fluid beds
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Important Processing Parameters
inlet and bed temperatures
relative humidity
atomization air pressure
liquid spray rate
droplet size
drying time
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Coating Problems
picking/chipping
roughness
sticking
film cracking/peeling
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Normal Coating
Description
Average
Reconstitution
weight
level
gain
HPMC based
Aqueous
system
11% to 15%
2.5 %
HPMC based
Organic
solvent
system
5%
2.5%
HPMC based
Aqueous/
Organic
Solvent/
Hydro
Alcoholic
system
PVA based
Aqueous
system
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Aqueous 11%
Organic Solvent
5%
2.5%
Hydro Alcoholic
9%
20% to 25%
2.5%
Application examples
Amoxycillin, Azithromycin, Atenolol,
Amlodipine, Amitriptyline, Ampicili n
Ciprofloxacin, Cephadroxil ,
Cimitidine, Calcium Tablets, Citrizine
, Chloroquine Phosphate,
Clarithromycin, Erythromycin,
Ferrous Fumarate, Famotidine,
Ferrous Sulphate, Ibuprof en,
Indapamine, Losartan Pot assium,
Levamisole, Methyl-Dopa,
Metronidazole+Tinidazole,
Metronidazole, Methyl Coblamine,
Mef enamic Acid, Metoprolol Tartrate,
Norfloxacin, Nifidipine,
Norfloxacin+Tinidazole, Ofloxacin,
Paracetamol, Quinine Sulphate,
Roxythromycin, Secnidazole,
Sildenafil Ci trate, Trimetazidine,
Tinidazole, Tinidazole-Doxycycline,
Tinidazole + Tetracycline, Verapamil
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Enteric-coated
Coating resists dissolution or disruption in stomach but not in
intestines. Used for drugs that are unstable, irritating to stomach
Description
Average
Reconstitution
weight
level
gain
Organic Enteric
Coating system,
Cellulose Acetate
Phthalate based
5%
Aqueous coating
system & Organic
enteric coating
system. Hydroxy
Propyl Methyl
Cellulose Phthalate
based system.
Organic: 5%
Aqueous: 10%
8%
Application ** examples
Aspirin, Bisacodyl
Dicl of enac Sodium
Doxylamine Succinate
8%
Garlic Tablets, Omeprazol,
Pentaprazole,
Aqueous 20%
Methacrylic acid
copolymer type "C"
USP/ NF based
system
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Pentoxyfyline, Rabeprazol ,
Hydro Alcoholic
10%
9%
Organic System
10%
CHEE 440
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Press Coating
Use of compression to form coat around a pre-formed core.
Used mainly to separate chemically incompatible materials
 also dual release patterns possible
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