Tablet Coating, Types and Their Compositions.

In Pharmaceutical Science there are many different doses form in which tablet are one of them. In which We are going to know about the details study of table coating and many more.

1. TABLET COATING, TYPES, COATING
MATERIAL & COATING PANS
SUBMITTED BY: RAJ KUMAR MANDAL
B. PHARM VTHSEM. 3
RD
YEAR
SUBJECT: INDUSTRIAL PHARMACY -I
(BP502T)
SUBMITTED TO: MR. RAHUL PAL
ASSISTANT PROFESSOR*, DEPARTMENT
OF PHARMACEUTICS
ISFCOLLEGE OF PHARMACY, MOGA
Pharmaceutics, Industrial Pharmacy-Ist Theory {BP502T}

2. INTRODUCTION
InPharmaceuticalSciencetherearemanydifferentdosesformwhichincludestablets,
pills,bend,pallets,etc.inwhichtabletisthemostcommonpharmaceuticaldosesform.
Coatingisacoveringthatisappliedtothesurfaceofanyobjectherethecoatingtermis
usedinthetabletmeanthecoveringofathinlayeroverasurfaceofatablet.
Coatingisauniquetechniquethroughwhichtabletarecoveredbyamaterialonitsouter
surface.Aftercoatingmaterialisappliedtoabatchoftabletintothecoatingpenresulting
onthissurfacetabletbecomecoverwithanextralayer.Spraypattern,nozzlespacing,
sizeofdroplets,etc.aresomeparameterswhichdependsonthecoatingtechnique.

3. PURPOSE OF COATING
#Tomaskingtasteordercolour
#Toinsurethephysicalandchemicalprotectionfromtheouterenvironmentlikeoxygenmoisturelightandother
form.
#Protectionofdrugfromthegastricenvironmentandotherfactor.
#EnhancePatientComplianceandImprovestabletappearanceandbranddifferentiation
#Preventtabletstickingandenhancementofself-lifeofthedrug
#Makingtooeasyforswellingorlargedoseform
#Preventthelosingofvolatileingredient.
#Followsfinecontoursofembossedlogo.
Canbeusedfortabletprinting.
#Modificationintherateofdrugreleaselikesustainedrepeatedanddelayreleasedandrreventionofdrug
incompatibility
#Makingincreasethephysicalstrengthalsoincreasethepackagingrate

4. DEFECTS IN TABLET COATING
1. Tablet Picking and Sticking
Cause:Thisoccurswhentabletssticktogether,
resultinginportionsofthetabletbeingtornoff.
Itisusuallycausedbyover-wettingofthe
tabletsduetoanexcessivesprayrateor
insufficientdrying.
Solution:Reducethesprayrateorincreasethe
dryingtemperatureorairflowtoevaporatethe
solventmorequickly.
2. Orange Peel Effect
Cause:Anunevenorroughcoatingsurface
(resemblingthetextureofanorangepeel)is
oftencausedbyhighviscosityofthecoating
solutionorrapiddryingbeforethecoatingcan
levelout.
Solution:Adjusttheviscosityofthecoating
solutionbyreducingtheconcentrationor
modifyingthesprayconditions.

5. CONT…
3. Cracking
Cause:Crackscanforminthecoatingdueto
improperdryingconditionsorover-application
ofthecoatingmaterial,leadingtointernalstress
inthefilm.
Solution:Adjustthedryingtemperatureto
ensurethecoatingdriesgraduallyand
uniformly.Also,checktheamountofplasticizer
inthecoatingsolutiontoimproveflexibility.
4. Bridging
Cause:Bridgingoccurswhenthecoating
solutioncoversthetablet’slogo,scoreline,or
anyembossedmarkings,makingthemless
visible.
Solution:Useamorefluidcoatingsolutionor
adjustthespraypatternandratetoensurethat
finedetailsremainintact.

6. CONT…
5. Colour Variation
Cause:Unevendistributionofthe
colorantinthecoatingsolutionor
impropermixingcanresultin
inconsistentcolouringofthetablets.
Solution:Ensureuniformdispersionof
colorantsinthesolutionandoptimize
thespraypatterntocoveralltablets
uniformly.
6. Chipping
Cause:Chippingiswhenpartsofthe
coatingbreakoffduringhandlingor
packaging.Itcanbecausedbyan
overlybrittlecoating,excessive
mechanicalstress,orinsufficient
plasticizerintheformula.
Solution:Increasetheplasticizer
contenttoenhancecoatingflexibilityor
reducemechanicalstressduringtablet
handling.

7. TYPES OF COATED TABLE
Type of
Coating
Purpose
Materials
Used
Advantages
Film Coating
Protects tablet,
controls drug
release
Polymers
(HPMC, PVP),
plasticizers
Thin, durable,
fast coating
process
Enteric
Coating
Protects drug
from stomach
acid, releases
in intestine
Cellulose
acetate
phthalate,
methacrylic
acid
copolymers
Prevents
stomach
irritation,
targeted
release
Sugar
Coating
Improves taste,
aesthetics
Sugar, gelatin,
calcium
carbonate
Glossy
appearance,
masks taste
Table: List of types of coating and description

8. (I) ENTERIC COATING
Itisamodificationtotheconventionalapproachofdrugtodissolvethedosageformin
gastricorstomach&releasethedruginGIT.
Itmayimproveorpreventthedegradationofdrugthroughgastricph.
Entericcoatingalsoimprovesbioavailabilityofdrug.
Inthiscoatalayerofpolymerthatpreventsdisintegrationinthegastricenvironment
whichmakesthedrugGastroresistant.
Itmayalsocausethedelayinactionofthedrug.
Techniqueinvolvedinentericcoatingistoprotectthetabletcorefromdisintegrationin
acidicenvironmentandontheotherhandhelpstosolubilizeinresponsetoanincreased
pH(6-8)ofintestine.
ItpreventsacidlabiledrugfromgastricoracidicpH&gastricenzymes.

9. CONT…
Manypolymerscanbeusedforentericcoatingtheyaredividedinto2types:
(A)Natural:Shellac
(B)Synthetic:CAP(celluloseacetatephthalate),PVAP(polyvinylacetatephthalate),
HPMCP(Hydroxypropylmethylcellulosephthalate)
HPMCPismostlyusedpolymerforentericcoatingasitiseasilysolubleinorganic
solvent&itisnothygroscopicasCAP,henceprovidemorestability.
ThesepolymersareinsolubleinlowerpH(2.5-4.5)andreleasethetabletinhigherpH
between(5-7)
Plasticizers:Triethylcitrate&diethylphthalate.

10. (II) FILM COATING
Itisprocesstoapplyathinlayerofpolymertoatablet
Itisusedtopreventtheoxidationwithenvironmentandhelpstoimprovetheshelllife
ofdrug
Thicknessoffilmisapproximately(25-100um).
Polymersarenon-toxicwithnopharmacologicalaction.
Providestrengthandpreventcracking
Thosetypesoffilmcoatingbasedoncoatingmaterial
(1)Organicfilmcoating
(2)Aquafilmcoating

11. Sr. No. Class Example
1. Cellulose Cellulose
HPMC, HPC, HEC, Methyl HEC
methylcellulose EC CMC Sodium
2. Vinyls PVC
3. Glycol PEG
4. Acrylates Ethyl acrylate, methyl mrthylate
copolymers

12. (III) SUGAR COATING
Thistypeofcoating,wecoverthetabletwithsugarsyrup/sucrosesolution.
Itmasksthetaste&makeiteasytoswallow.
Itmaybecoloredormaybeuncolored.
Mostlyusedforpediatricandgeriatricpatients.
Shapeofsugar-coatedtabletsaredeeplyconvexcorewithminimaledges.
Sugarcoatingenhancestheweightoftabletby50-100%
Keypointestobenotedduringsugarcoating:
(1)Quantityofsugarsolutiontobeaddedforcoatingascoatingmaterial.
(2)Rateofpouringofsolution.
(3)speedoftumblingofpanandapplicationofairdryer.

13. CONT…
StepsinvolvedinSugarCoating:
(i)Sealing:itisdonetopreventmoisturedamageortowaterproofingofthetablet.
(ii)Subcoating:itisdonetoroundofftheedgesoftablet
(iii)Syruping:layerofsugarsyrup/sucrosesolutionisaddedwithsomebindersuchas
acacia,gelatinalongwithcoatingmaterialsuchascalciumcarbonate,titaniumdioxide
alongwithdrying.
(iv)Finishing:itmayincludeanoutercoveringtocoverroughsurface&toincrease
bulkoftabletalsoitincludesthecoloringoftheoftheroughsugar-coatedtabletas
required.
(v)Polishing:Itgivesashining/glossyouterappearancewhichmakethetablet
attractive,polishingisdonebyusingbeeswax,&candelillawaxmixture.

14. COATING PANS

15. 1. CONVENTIONAL COATING PANS
Itisalsoknownasastandardcoatingpan.
Circularmetalpanwhichareinclinedwiththe40degreeangle.
Having8to60inchdiameter
Rotatedonitshorizontalaxisbyamotor.
Heatedairissuppliedbytheinlethairsupplyinordertopreventfromsticking.
Exhaustbymeansofdusts.
Coatingsolutionareappliedtothetabletbylandingorspring
Useofatomizingsystemtoproduceeventdistributionofcoatingsolution.

16. CONT…
i)PELLIGRINICOATINGPAN
Theyareavailablefromtherangeof10to1000kgbatch.Theyaresuitableforthesugarcoatedtabletsbutnotforthefilm
coatedduetothelimitationinthedrawingcomparability.CoatingbuffetPananddiffuserthatdistributesthedryingair
uniformly
LimitationwasovercomebyinstallingGlattimpressionswordairhandlingsystemtoimprovedryingefficiency.
ii)GLATTIMPRESSIONSWORDCOATINGPAN
Inthistypeofcoatinginstrumentstwosystemsarefollowed
a)PLGSYSTEM
Inthisthehotairinletbyaswordandexhaustairbyplenum
b)inthisthehotairinletbyaplenumandexhaustby2-perforatedswords.
iii)IMMERSIONTUBECOATINGPAN
ThistypeofputtingPanhavealongtubewithaspringnozzleatitstip.Hotairgetsintothroughthetubeintotabletbed.The
driedairflowupwardandexhaustedbytheconventionaldust
Onthesametimerapidprocessinghavebeenreportedforbothfilmandsugarcoatingwithinthesystem.

17. 2. PERFORATED COATING PANS
Ananothertypeofcoatingpan.
Itconsistofpartialorfullperforateddrumthatrotateonitshorizontalaxis
Onthesametimetheentiresystemremainsinclosedinasealhousing.
Tabletsareintheperforatedpanenhancingdryingefficiency.Thecoatingsolutionisa
sprayedwhilewarmaircirculatethroughtheperforationinsuringeventcoatingand
effectivedrying.
Theyareidealforfilmandentericcoatingthatprovideabettercontrolovercoating
qualityanddrawingifyoucanseecomparetothetraditionalpans

18. CONT…
i) ACCELA COAT PAN
This type of pants are fully perforated, contains mixing blades.Inlet air is by a plenum in contact with the top of the pan. Air is
exhausted by the plenum located below the pan.
ii)DUMMOULIN IDA.X. COATING EQUIPMENT
1) Fully perforated cylindrical central section.
2) The two air plenums that function as both inlet or exhaust air systems are located in contact with the outside of the pan.
3) A third plenum, connected to a slotted tube located inside the pan and above the cascading product bed allows inlet air only to
be directed onto the surface of product being coated.
4) Air flows, single flow, reversed single flow, double flowand direct double flow
iii) GLATT PAN-COATING EQUIPMENT
1) Similar to that of AccelaCota.
2) A divided air plenum located beneath the moving tablet bed enables air to be blown into or exhausted from the pan through
either or both of the two sections
3) In addition, another air plenum, connected to an opening above the door (similar to that in a HI coater also allows air to be
blown into exhausted from the pan and quite expensive.

19. CONT…
iv)HI-COATERPAN
It'sconsistsof4perforatedsegmentswhichareperpendiculartoeachotherandeachoftheseperforationsactsasanopeningforair
outletwhichisfixedtotheexteriorofthepansurfaceanddryingairisintroducedintopanthroughanopeninglocatedoninside
peripheryoftopofthepan.
v)DRIACOATER
Introducesdryingairthroughhallowperforatedbaffleslocatedoninsideperipheryofdrumandexhaustisfrombackofthepan.
Differentairflows
a)directflow:airinatthetopandexhaustedthroughbaffleslocatedbeneathtabletbed.
b)reverseflowA:airinthroughbaffleslocatedbeneath,tabletbedandexhaustedviabaffletopofpan.
c)reverseflowB:airinthroughbaffleslocatedbeneathtabletbed,andexhaustedviaplenumconnectedtoopeningatbackofpan.
vi)HUTTLINBUTTERFLYPAN
Ithasaseriesoflarge,angled,slottedopeningin,thepanwallatthejunctionofthecylindricalportionwitheachofthefrontorback
panels.Theseopeningspermitairtobeexhaustedfromthepananddryingairisappliedtothesurfaceofthebedoftheproductbeing
coatedbyMeartube.
Frontandbackofthepancanbedisconnectedfromthecylindrical,centralsectionandhingeddown.

20. 3. FLUIDIZED BED COATING PANS
InthistypeofcoatingpanFluidizationtechniqueisused.Airisusedtosuspend,and
floordiesthetabletorgranuleswhichcreateauniformbed.Thecoatingsolutionis
sprayedontotheparticleastheymoveintheairstream,thatensuringevencoating
distribution.
Whilethecoatingsolutionissprayed,hotdryertheparticleinrealtimewhichprevent
agglomerationandallowingforeffectivecoating.
Afluidizedbedcoatingpanisatypeofequipmentusedinthepharmaceutical,
chemical,andfoodindustriesforcoatingparticlessuchasgranules,pellets,or
powders.Theprocessusesacombinationoffluidizationandspraycoating,makingit
idealforapplicationslikecontrolled-releasedrugformulationsortheapplicationof
protectivecoatings.

21. CONT…
PrincipleofOperation:
Fluidization:Particlestobecoatedaresuspendedinanairstream,whichcausesthemtobehavelikeafluid.
Thisensuresthateachparticleisevenlyexposedtothecoatingsolution.
Spraying:Whiletheparticlesaresuspended,acoatingsolution(oftenapolymerdissolvedinasolventor
water)issprayedintothebed.Thesolutionadherestotheparticles.
Drying:Thehotairusedforfluidizationalsoevaporatesthesolventormoistureinthecoatingsolution,
leavingbehindauniformlayerontheparticlesurface.
TypesofFluidizedBedCoatingProcesses:
Top-SprayCoating:Thespraynozzleispositionedabovethefluidizedparticles.Thisisoftenusedfor
granulationandcoatingprocesses.
Bottom-SprayCoating:Thespraynozzleisplacedatthebottom,andcoatingisappliedasparticlesare
pushedupwardsbytheairstream.Thisiscommonforcontrolled-releasecoatings.
TangentialSpray:Usedforapplyinghigh-loadcoatings,thenozzleispositionedatanangletothebed.

22. CONCLUSION
Tabletcoatingisacrucialprocessinpharmaceuticalmanufacturingthatenhancesthe
stability,aesthetics,andfunctionalityoftabletsbyapplyingathinlayerofcoating
material.Themaintypesoftabletcoatingsincludesugarcoating,filmcoating,and
entericcoating.
Sugarcoatingsimprovetasteandappearance,whilefilmcoatings,usingpolymerslike
HPMC,offerprotectionandcontroldrugrelease.Entericcoatingsprotectdrugsfrom
stomachacidandensurereleaseintheintestines.Commoncoatingmaterialsinclude
polymers,plasticizers,andcolorants.Coatingpans,suchasconventionalcoating
pans,perforatedcoatingpans,andfluidizedbedcoaters,areusedtoachieveuniform
coatingapplicationthroughprocesseslikespraying,drying,andmixing.

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