UNIT- II Tablets coating and FC- QC TEST

Tablet coating
Formulation of Coating
METHODS OF COATING
Defects in Tablet Coatings
QUALITY CONTROL TESTS

1. UNIT-II
by Mr. Madhav Korde

2. Tablet Coatings
➢Tablet coatingis the application of a layer or filmto the surface of a tablet to
enhance its properties
➢Tablet coating is one of the oldest pharmaceutical processes.
➢It involves applying a sugar or polymeric coat on the tablet for taste masking,
odourmasking, physical and chemical protection, protecting the drug in the
stomachand controlling its release profile.

3. Need for Tablet Coating?
✓Protectfrom environmental factors (moisture, light).
✓Improve tablet stability.
✓Mask unpleasant taste or odour.
✓To improvethe appearance of tablets.
✓Modifydrug release (e.g., enteric coating).
✓To Produce sustained released products.

4. Tablet Coatings
Advantages
➢Enhances patient compliance.
➢Masks drug taste.
➢Provides controlled releaseof the drug.
➢Improves mechanical strength and ease of handling.
➢Improves tablet appearance and brand differentiation.
➢Prevents tablet sticking.
➢Follows fine contours of embossed characters or logos.
➢Maintains stability and strength during tablet handling.
➢Provides smoother tablet finishing.
➢Aids in swallowing larger tablets.
➢Can be used for tablet printing.
➢Protects drug from stomach degradation.
➢Preventsdrug-induced irritation at specific gastrointestinal tract sites.
➢Targets drug release to specific sites in the gastrointestinal tract.

5. Tablet Coatings
TypesofTabletCoating
1.SugarCoating:Involvesmultiplelayers(seal,subcoat,syrupcoat,polishing)typically
usedfortastemaskingandappearanceimprovement.
2.FilmCoating:Applicationofathinpolymerfilm.Fasterprocessthansugarcoating,
thinnerandmoreuniformlayer,andhasgreaterresistancetochipping
3.EntericCoating:Thesetabletsarecoatedtowithstandtheacidicenvironmentofthe
stomachandreleasedrugsslowlyinthesmallintestine,ensuringoptimalabsorptioninthe
gastrointestinaltract.
4.SpecializedCoatings(e.g.,CompressionCoating/Presscoating):Applicationofadrycoating
layerbycompression.
5.GelatinCoatedTablets:Thesearecapsule-shapedcompressedtabletscoatedwithgelatinlayer.

6. Tablet Coatings
1.SugarCoating:
➢Sugarcoatingisoneoftheoldestandmosttraditionalmethodsoftabletcoating
➢Usedprimarilyforimprovingtheappearanceandmaskingthetasteoftablets.
➢Theprocessinvolvestheapplicationofseverallayersofcoatingmaterials,resultinginathick,
glossy,andpolishedfinish.
Steps Involved in Sugar Coating Process:
1.Sealing (Waterproofing):Protects the tablet core from moisture.
2.Subcoating:Builds up tablet size and provides a smooth surface.
3.Smoothing (Grossing):Smooths the surface for even color application.
4.Color Coating:Adds color to be physically attractive.
5.Polishing:This creates a shiny, glossy finish.
6.Imprinting (Optional):Adds identification markings using edible inks.

7. 1.SugarCoating
StepsInvolvedintheSugarCoatingProcess:
1.Sealing(Waterproofing):
➢Athinlayerofthesealingsolutionissprayedontothetablets,followedbydrying.Thisstepmay
berepeatedmultipletimestoensurepropersealing.
➢Shellac,celluloseacetatephthalate(CAP),orotherhydrophobicmaterialsdissolvedinan
organicsolvent.
➢Thesealcoatprovidesamoisturebarrierandhardensthetablettominimizeattritioneffects.
➢Commonmaterialsusedasasealantincludeshellac,zinc,celluloseacetatephthalate,polyvinyl
acetatephthalate,hydroxypropylcellulose,hydroxypropyl-methylcellulose,etc.
2.Subcoating:
➢Sub-coatingisthestepfromwheretheactualsugar-coatingprocessbegins.
➢Providesrapidbuild-upnecessarytoroundupthetabletedges.
➢Italsoactsasthefoundationforsmoothingandcolorcoating.
➢Athinlayerofadhesivegumsolutionisappliedtothesealedtablets.
➢Sugar,starch,andcalciumcarbonateblendisdustedontothewettablets.
➢Thetabletsaredried,whichisrepeateduntilthedesiredtabletsizeisachieved.
➢Increaseweightby50-100%atthisstep.
➢Thus,sub-coatingisasandwichofalternatelayerofgumandpowder.
➢Itisnecessarytoremovethebulkwateraftereachapplicationofcoatingsyrup.

8. 1.SugarCoating
StepsInvolvedintheSugarCoatingProcess:
3.Smoothing(Grossing):
➢Thisisdonetogivesugarcoatsopacityandcolortothetablet,Severalcoatsofsyrupare
applied.
➢Thegrossingsmoothensandroundsoffthetablet’sirregularitiesandbuildsthetabletstothe
desiredsize.
➢Asyrupsolutionisappliedthinlytosmootharoughsubcoatedsurface,thentabletsare
rolledinacoatingpanuntilasmoothsurfaceisachieved.
➢Thissyrupgenerallycontainspigments,starch,gelatin,acacia,oropacifier(ifrequired).
➢Theprocessisrepeateduntiluniformcolouredtabltesareobtained.
4.ColorCoating:
➢Thisstageisoftencriticalinthesuccessfulcompletionofasugar-coatingprocess.
➢Involvesmultipleapplicationofsyrupsolution(60-70%sugarsolid)containingthe
requisitecoloringmaterialsnecessarytoachievethedesiredshade.
➢Sucrosesyrupcontainingcolorants(water-solubledyesorlakepigments).
➢Itgivecolorandfinishedsizeofthetablets.

9. 1.SugarCoating
StepsInvolvedintheSugarCoatingProcess:
5.Polishing:
➢Thefinalstepofsugarcoatingprocessispolishing
➢Togivethetabletsaglossy,shinyappearance.
➢Waxeslikecarnaubawaxorbeeswax,sometimescombinedwithpolishingagents.
➢Typically,oneortwolayersofwaxaresufficientforpolishing.
6.Imprinting(Optional):
➢Imprintingisdoneusingspecialprintingmachinesthatapplythedesireddesigntothe
surfaceofthepolishedtablets.
➢Toaddidentificationmarks,logos,Productname,dosagestrengthorotherinformationtothe
tablets.
➢Inksoredibledyes.

10. 1.SugarCoating
Advantages:
✓Taste&OdorMasking:Excellentformaskingunpleasantflavors.
✓EnhancedAppearance:Providesaglossy,smoothfinish.
✓Stability:Protectsthetabletcorefrommoistureandlight.
✓PatientCompliance:Attractiveandpalatable,idealforpediatrics.
✓BrandDifferentiation:Distinctiveappearanceforproductbranding.
Disadvantages:
✓Time-Consuming:Labor-intensive,multiplesteps.
✓IncreasedSize/Weight:Multiplelayersincreasetabletbulk.
✓CostlyManufacturing:Expensiveandcomplexcomparedtofilmcoating.
✓LimitedFunctionality:Nocontrolledordelayedreleasecapabilities.
✓MoistureSensitivity:Hygroscopic,requiringpropersealing.

11. 2.FilmCoating
➢Filmcoatinginvolvesapplyingathin,uniformpolymerlayer
overatablet.It'safasterandmoreefficientmethodcompared
tosugarcoating.
➢Usesconventionalpanequipmentorsophisticatedequipmentforautomation
andfastercoatingtime.
➢Polymerissolubilizedintoasolvent,additivesadded,andsprayedontoa
rotatingtabletbed.
➢Dryingconditionsremovethesolvent,resultinginathindepositionofcoating
materialaroundeachtabletcore.
➢Sprayprocessiscommonlyused,withAccelaCotabeingaprototype.
➢Forfluidizedbedcoating,veryhardtabletsarerequired.

12. 2.FilmCoating
CharacteristicsofFilmCoatingProcess
➢Minimizesweightgain(2-3%)oftablets.
➢Lessenstabletdisintegration.
➢Quick,single-stageprocess.
➢Easytoautomate,reducingrelianceonskilled
operators.
➢Maintainsoriginalcoreshapeforembossing.
➢Requiresexpensiveequipmentandlargeplant
space.
➢Highinstallationandenergycosts.
IdealRequirementsforFilmCoating
Materials
1.Solubleinselectedsolvent.
2.Dissolveinwaterorshowdesiredsolubility
(loworpH-dependent).
3.Produceasmooth,aestheticallypleasingfinish.
4.Stableagainstheat,light,moisture,air,and
substrate.
5.Neutralincolor,taste,andodorduringcoating.
6.Compatiblewithotherexcipients.
7.Non-toxic,nopharmacologicalactivity.
8.Resistanttocracking.
9.Avoidbridging/fillingindebossedtablets.
10.Compatiblewithprintingmethods.

13. 2.FilmCoating
StepsinFilmCoating
1.PreparationofCoatingSolution:Mixpolymers,plasticizers,
colorants,andsolvents(aqueousororganic).
2.TabletLoading:Loadtabletsintothecoatingpanorfluidizedbed
coater.
3.AtomizationandSpraying:Spraythecoatingsolutionontothe
rotatingorfluidizedtablets.
4.Drying:Usewarmairtoevaporatethesolvent,leavingauniform
film.
5.PolishingandFinishing(Optional):Enhancetabletshineandensure
smoothness.

14. 2.FilmCoating
AdvantagesofFilmCoating
1.Faster Process:Requires less time compared to sugar coating.
2.Thinner Coating:Produces lighter and less bulky tablets.
3.Improved Appearance:Smooth, glossy finish with uniform color.
4.Enhanced Protection:Shields tablets from moisture, light, and mechanical stress.
5.Customizable Release Profiles:Suitable for immediate, controlled, or delayed release.
6.Taste/Odor Masking:Effectively conceals unpleasant taste or smell.

15. 3.EntericCoating
➢Definition:Entericcoatingisaprotectivelayerappliedtotabletsthatprevents
dissolutioninthestomach’sacidicenvironment,allowingthedrugtoreleaseinthe
moreneutralpHoftheintestines.
➢Protectacid-sensitivedrugs,preventstomachirritation,andtargetdrugreleasetothe
intestines.
➢Commonpolymersincludecelluloseacetatephthalate(CAP),methacrylicacid
copolymers,andpolyvinylacetatephthalate(PVAP).
➢Propercoatingthicknessandevendistributionarecrucialtoensurethecoatingremains
intactinthestomachanddissolvesintheintestines.

16. 3.EntericCoating
Enteric Coating Process
1)Preparation of Coating Solution: Mixing enteric polymers with solvents and plasticizers.
2)Tablet Loading: Loading tablets into a coating pan or fluidized bed coater.
3)Spraying and Coating: Spraying enteric coating solution onto tablets for even coverage.
4)Drying: Apply warm air to evaporate the solvent, forming a uniform coating layer.

17. 3.EntericCoating
Advantages:
✓Protectsdrugsfromstomachacid.
✓Reducesgastricirritation.
✓Targetsdrugreleasetotheintestines.
✓Allowsfordelayedorsite-specificdrugdelivery.
DisadvantagesofEntericCoating
➢ComplexandCostly:Requiresspecializedmaterialsandequipment,raising
productioncosts.
➢DelayedOnset:Drugreleaseisdelayeduntilreachingtheintestines,unsuitablefor
drugsneedingrapidaction.
➢IncompleteCoatingRisk:Inconsistentcoatingmayleadtoprematuredissolutionin
thestomach.
➢StabilityIssues:Pronetodegradationinhighhumidity/temperature,affectingdrug
effectiveness.
➢DrugIncompatibility:Notidealfordrugsrequiringimmediatereleaseorstomach
absorption.
➢TabletFracturing:Enteric-coatedtabletsaremorebrittle,increasingtheriskof
crackingduringhandling.

18. 4.CompressionCoating
➢Compressioncoating,alsoknownaspresscoating,isaspecializedcoating
techniquewhereanouterlayeriscompressedontoacoretabletwithoutthe
useofsolventsorliquids.
➢Acompression-cotedtabletisasysteminwhichtheentiresurfaceoftheinner
coreissurroundedbythecoatandthesecoatspreventdrugreleasefromthe
coreuntilthepolymericcodeisentirelyeroded.
➢Typicallyinvolvesexcipientslikecellulosederivativesorothercompressible
materials.
➢Compression-coatedformulationscanbeusedtoprotecthygroscopiclight-
sensitive,oxygenoracid-labiledrugs,ortoseparateincompetentdrugs
fromeachother.

19. 4.CompressionCoating/Presscoating
Compression Coating Process
1.Forming core tablet: Compressing active ingredient into a tablet.
2.Compression of coating layer: Compressing powder or granulate
material around a core tablet.
Advantages:
➢No need for solvents or drying processes, making it suitable for
moisture-sensitive drugs.
➢Allowsfor complex drug release profiles, such as delayed or
pulsatile release.
➢Offers protection to the core tablet from environmental factors.

20. 3.Coating
Compression Coating Benefitsand Applications
Benefits:
➢Solvent-Free: Ideal for drugs sensitive to moisture or solvents.
➢Versatile Release Profiles: Can create layered tablets with immediate
and delayed-release cores.
➢Dual-Release Capabilities: Allows sequential release of different
drugs or the same drug at different times.
➢Enhanced Stability: Protects unstable or sensitive core drugs from
environmental conditions.
Applications: Modified Release Tablets, Fixed-Dose Combinations,
Protective Coating.

21. Formulation of Coating
1.Polymers (Film-forming materials)
2.Plasticizers
3.Solvents
4.Colorants
5.Opaquants
6.Miscellaneous coating solution components.

22. FormulationofCoating
1.Polymers(Film-formingmaterials)
i.HydroxyPropylMethylCellulose(HPMC)
✓Availableinvariousviscositygrades.
✓Idealforairsuspensionandpanspraycoatingsystemsduetosolubilityingastricfluid,
organic,andaqueoussolvents.
✓Doesn'taffecttabletdisintegrationordrugavailability.
✓Cheap,flexible,andhighlyresistanttoheatandmoisture.
✓Notasteorodour;easyincorporationofcolorandotheradditives.
✓Maybridgeorfilldebossedtabletsurfaceswhenusedalone.
ii.Ethylcellulose:Usedforsustained-releasecoatings.
iii.CelluloseAcetatePhthalate(CAP):Commoninentericcoatings.
iv.Povidone
✓Polymerisationdegreedeterminesmolecularweight.
✓AvailableinK-15,K-30,K-60,andK-90viscositygrades.
✓K-30gradeusedasatabletbinderandcoating.
✓Excellentsolubilityinorganicsolvents,water,gastric,andintestinalfluids.
✓Cross-linkedwithothermaterialsforentericfilms.
✓Improvescolorantdispersionincoatingsolution.

23. FormulationofCoating
2.Solvents
✓Dissolveordispersepolymersandadditives.
✓Conveythemtothesubstratesurface.
✓Usedaloneorincombinationwithwater,ethanol,methanol,isopropanol,chloroform,
acetone,andmethylenechloride.
✓Wateristhemostcommonsolvent.
✓Non-aqueoussolventsusedfordrugshydrolyzinginwater.
3.Plasticizers
✓Polymericmaterialsoftenforma3Dhoneycombarrangementaftersolventremoval.
✓Internalorexternalplasticizingtechniquesareusedtomodifyfilmquality.
✓Acombinationofplasticizerscanbeusedfordesiredeffects.
✓Therecommendedplasticizerconcentrationisdeterminedbytheweightofthefilmformer,
withrecommendedlevelsrangingfrom1-50%.
✓Commonplasticizersincludecastoroil,propyleneglycol,glycerine,lowmolecularweight
PEG,andsurfactants.
✓PEGandPGarecommonlyusedforaqueouscoating,whilecastoroilandspansareusedfor
organic-solventbasecoating.

24. FormulationofCoating
4.Colourants
✓Colourantscanbeusedinsolutionorsuspensionform.
✓Powderedcolorants(<10microns)arerecommendedforproperdistribution
✓CommoncolorantsarecertifiedFDandC,orDandCcolorants.
✓Concentrationdependsondesiredcolourshade,dyetype
✓Lightshaderequireslessthan0.01%concentration;darkcolourrequiresmorethan2%.
✓Inorganicmaterialsandnaturalcolouringmaterialsarealsoused.
✓Magentareddyeisnon-absorbableinbiologicalsystemsandresistanttodegradationin
theGIT(opaquecolourconcentrateforfilmcoating).
5.Opacifiers
✓Opacifiersarefineinorganicpowdersusedtoprovidepastelcolorsandincreasefilm
coverageTheyaddbulkandopacityandimprovecoatingtexture.
✓Theymaskthecolorofthetabletcoreandareinexpensive.
✓Commonopacifiersincludetitaniumdioxide,silicates,carbonates,oxides,andhydroxides.
✓Pigmentsinopaquefilmshavegoodhidingpowerandhighlightintagliations.

25. FormulationofCoating
6.MiscellaneousCoatingSolutionComponents
i.Flavours,sweeteners,surfactants,antioxidants,antimicrobials,etc.maybe
incorporatedintothecoatingsolution.
ii.CelluloseAcetatePhthalate(CAP):Widelyusedinindustries,Aquatericisareconstituted
colloidaldispersionoflatexparticles.
CAPdissolvesonlyatpHabove6,delaysdrugabsorption,ishygroscopic,permeabletomoisture,
andsusceptibletohydrolyticremovalofphthalicandaceticacid.
CAPfilmsarebrittleandareusuallyusedwithotherhydrophobicfilm-formingmaterials.
iii.AcrylatePolymers:EudragitLandSarecommerciallyavailableentericacrylicresinsthat
producefilmsresistanttogastricfluid.TheydissolveatpH6and7,respectively.
iv.HydroxyPropylMethylCellulosePhthalate:HPMCP50,55,and55–sarewidely
used,anddissolveatapH5-5.5.
v.PolyvinylAcetatePhthalate:SimilartoHP-55instabilityandpH-dependentsolubility.

26. METHODS OF COATING
➢Inmostcases,thecoatingprocessisthelastcriticalstepinthetabletproductioncycle.
➢Tabletcoatingistheapplicationofcoatingcompositiontothemovingbedofthetabletwiththe
concurrentuseofheatedairtofacilitatetheevaporationofthesolvent.
➢Thedistributionofcoatingisaccomplishedbythemovementoftabletsasperpendicular(coatingpan)
orvertical(airsuspensioncoater)totheapplicationofcoatingcomposition
➢Thesuccessfulapplicationofcoatingsolutionformulatothetabletprovidesthevisual
characteristicsfortheproduct.
➢Thus,thequalityoftheproductmaybejudgedonthefinalproductionstep.
➢Thetypeofcoatingdependsontheapplicationtype,thedurabilityandtoughnessofthetabletcore,and
theefficiencyoftheprocess.
➢Sugarcoatingisstillawidelyusedcoatingprocessbecauseoftheexcellenttabletappearanceis
achieved.
CoatingMethods
i.PanCoating
ii.FluidizedBedCoating(AirSuspension)
iii.DipCoating
iv.CompressionCoating(PressCoating)

27. METHODS OF COATING
EquipmentEmployedinCoating
1)Standardcoatingpan
i)Pellegrinipansystem,
ii)Immersionswordsystem,and
iii)Immersiontubesystem.
2)Perforatedcoatingpan
i)Accelacotasystem,
ii)Hi-coatersystem,
iii)Glattcoatersystem,and
iv)Driacoatedsystem.
3)Fluidisedbed(airsuspension)coater
➢Thegeneraltrendhasbeentowardenergy-efficient,automatedsystemsto
shortenthetotalcoatingtimeandreduceoperatorparticipationinthecoating
process.

28. METHODS OF COATING
EquipmentEmployedinCoating
1.Standardcoatingpan
➢Conventionalcoatingpan/pancoater.
➢Tabletsarerotatedinapan8-60inchesindiameterandarerotated
onitshorizontalaxisbyamotor.,causingatumblingeffect,
wherethecoatingsolutionisappliedgradually,andheatedairis
introducedtopreventclumping.
Construction:
i.RotatingPan:Alarge,circularmetalpan(typicallycopperor
stainlesssteel)tiltedatanangleandattachedtoamotorfor
rotation.
ii.SpraySystem:Aspraynozzledeliversthecoatingsolution
evenlyoverthetablets.
iii.HotAirBlower:Providesheatedairtodrythecoatingduring
theprocess.
iv.ExhaustSystem:Removesexcessmoistureandsolvent
vapors.

29. METHODS OF COATING
EquipmentEmployedinCoating
1.Standardcoatingpan
WorkingProcess:
i.Loading:Tabletsareloadedintotherotatingpan.
ii.CoatingApplication:
i.Asthepanrotates,thecoatingsolutionissprayedontothetumblingtablets.
ii.Thetumblingactionensuresevendistributionofthecoating.
iii.Drying:Heatedairisblownintothepantodrythecoatingasit'sapplied,
avoidingtabletsstickingtogether.
iv.Repetition:Thisprocessisrepeatedincyclesuntilthedesiredcoatingthickness
isachieved.
v.FinalDrying:Afterthefinalcoat,thetabletsundergothoroughdryingtoensure
thecoatingishardandstable.
Applications:Sugar,film,andentericcoatingsontabletsandpills.

30. METHODS OF COATING
1.Standardcoatingpan
Pellegrinipansystem,ii)Immersionswordsystem,andiii)Immersiontubesystem.

31. METHODS OF COATING
2.Perforatedcoatingpan
➢Thisisanotherpopulartypeofcoatingpan
➢Itconsistsofapartialorfullperforateddrum,whichrotatesonahorizontalaxis.
➢Atthesametime,theentiresystemremainsenclosedinasealhousing.
➢Tabletsarerotatedinaperforatedpan,enhancingdryingefficiency.Thecoatingsolutionis
sprayedwhilewarmaircirculatesthroughtheperforations,ensuringevencoatingand
effectivedrying.
PerforatedPanconsistof:
➢Stainlesssteelpanwithperforationsforairpassage.
➢SpraySystemdeliverscoatingsolutionontotablets.
➢AirHandlingUnitHotAirInletforquickdrying.
➢ExhaustSystemforoptimaldryingconditions.
➢Motor-drivensystemforcontrolledpanrotation.
➢Applications:Idealforfilmandentericcoatings,providingbettercontrolovercoating
qualityanddryingefficiencycomparedtotraditionalpans.

32. METHODS OF COATING
2.Perforatedcoatingpan
A-Accelacotasystem,B-Hi-coatersystem,C-Driacoatedsystem.

33. METHODS OF COATING
2.Perforatedcoatingpan

34. METHODS OF COATING
3.Fluidisedbed(airsuspension)coater
➢Fluidization:Inafluidizedbedcoater,airisusedto
suspendandfluidizethetabletsorgranules,creatinga
uniformbed.Thecoatingsolutionissprayedontothe
particlesastheymoveintheairstream,ensuringeven
coatingdistribution.
➢Whilethecoatingsolutionissprayed,hotairdriesthe
particlesinrealtime,preventingagglomerationand
allowingforefficientcoating.

35. METHODS OF COATING
3.Fluidisedbed(airsuspension)coater
WorkingProcess:
i.Loading:Particlesortabletsareloadedintoafluidizedbed
chamber.
ii.Fluidization:Airisblownfromthebottom,causingparticles
tobecomesuspendedandfluidized.
iii.CoatingApplication:Thecoatingsolutionissprayed
throughnozzles,ensuringevencoverage.
iv.SimultaneousDrying:Heatfromfluidizationalsodriesthe
coating,preventingagglomeration.
v.ContinuousProcess:Fluidization,spraying,anddrying
continueuntildesiredcoatingthicknessandqualityare
achieved.
vi.FinalDrying:Particlesundergoafinaldryingphaseto
solidifythecoating.
➢Applications:Widelyusedforfilmcoating,entericcoating,
andcontrolled-releaseformulationsduetoitsabilityto
producehighlyuniformcoatingswithefficientdrying.

36. Defects in Tablet Coatings

37. Defects in Tablet Coatings
1.PickingandSticking:Tabletssticktogetherortothecoatingpan
duetoinadequatedrying.
Causes:
➢Excessivecoatingsolution,
➢Insufficientdryingair.
➢Impropertabletdesign.
Remedies:
➢Reducetheamountofcoatingsolution.
➢Increasedryingairtemperatureandairflow.
➢Adjustformulationforlesstackiness.

38. Defects in Tablet Coatings
2.Orange Peel Effect(roughness): Uneven coating surface with a rough,
bumpy texture resembling orange peel.
Causes:
➢Viscous coating solution or improper spray application.
➢To rapid drying
Remedies:
➢Dilute the coating solution.
➢Adjust spray pressure and nozzle settings for a finer mist.
➢Increase drying air temperature to smooth the surface.

39. Defects in Tablet Coatings
3.Edge Chipping and Erosion: Chips or cracks in the coating, often at
tablet edges.
Causes
➢Brittle coating due to inadequate plasticizer or improper drying.
Remedies
➢Increase plasticizer in the coating formulation.
➢Adjust drying conditions to avoid over-drying.
➢Select a polymer with a higher molecular weight.

40. Defects in Tablet Coatings
4.Blooming: A dull, hazy appearance on the tablet surface due to the
crystallization of the plasticizer.
Causes
➢High humidity during coating or storage.
➢To high processing temperature.
➢Low mol. wt. plasticizer.
Remedies
➢Control humidity during the coating process.
➢Use less hygroscopic plasticizers.

41. Defects in Tablet Coatings
5.Bridging: Coating fills or bridges over tablet logos or debossed markings.
Causes:
➢Excessive coating thickness or improper application.
➢Poor logo design
➢Spray rate too high.
➢Product temperature, too low.
➢Poor plasticized coatings system.
Remedies:
➢Reduce coating solution application.
➢Increase atomization of the spray for finer particles.
➢Use lower viscosity coating solutions.

42. Defects in Tablet Coatings
6.Cracking: Cracks appear in the coating due to excessive
mechanical stress or brittle coating.
Causes:
➢Improper drying or insufficient plasticizer.
➢Internal stresses in the film exceed tensile strength of the film.
Remedies:
➢Increase plasticizer content to improve flexibility.
➢Optimize drying conditions to prevent over-drying.

43. Defects in Tablet Coatings
7.Color Variation: Inconsistent color on the coated tablets.
Causes:
➢Uneven mixing of colorant.
➢Improper spray distribution.
➢Inconsistent drying.
➢Migration of soluble dyes-plasticizers and other additives during drying.
Remedies:
➢Ensure uniform mixing of the colorant.
➢Optimize spray pattern and drying conditions for even coating.

44. Defects in Tablet Coatings
8.Peeling: Coating peels off from the tablet surface.
Causes:
➢Poor adhesion of the coating to the tablet core.
Remedies:
➢Improve tablet surface smoothness before coating.
➢Adjust coating formulation for better adhesion.
➢Optimize the application process for even coating distribution.

45. Defects in Tablet Coatings
9.Twinning: Two or more tablets stick together during the coating process,
forming twins or clusters.
Causes:
➢Insufficient drying air or inappropriate spraying conditions.
➢Tablets with flat surfaces, promoting adhesion
Remedies:
➢Reduce coating solution application per spray cycle.
➢Adjust spray rate and atomization settings for finer droplets.
➢Increase drying efficiency by increasing air temperature and flow.
➢Ensure consistent drying throughout the process.
➢Use biconvex tablets for reduced stickiness.

46. Defects in Tablet Coatings
10.Blistering: Blistering occurs when the coating layer forms bubbles or
blisters, resulting in a swollen appearance on the tablet surface.
Causes:
➢Entrapment of volatile solvents beneath the coating layer.
➢Rapid evaporation of solvents due to high drying temperatures.
➢Inadequate adhesion of the coating to the tablet surface.
Remedies:
➢Lower drying air temperature for gradual solvent evaporation.
➢Adjust the coating solution to include slower-evaporating solvents or increase
plasticizer content.
➢Enhance adhesion by adjusting the coating process.

47. Defects in Tablet Coatings

48. QUALITY CONTROL TESTS
✓Qualitycontrolinvolvesproducttestingfordefectsandtimelyreportingto
management.
✓Toensurethesafety,efficacy,andqualityoftabletsbeforetheyreachthemarket.
✓Compliancewithpharmaceuticalspecificationsiscrucialforproductquality.
✓Adherencetopharmacopoeialstandards(e.g.,USP,BP,IP)isessential.
✓In-processandfinishedproductqualitycontroltestsensureproductsafetybefore
marketing.
✓In-ProcessControls(IPC)involvemeasurestakenduringthemanufacturing
process.
✓FinishedProductControls(FPC)areperformedpost-manufacturing,focusingon
qualitativeandquantitativecharacteristics,testprocedures,andproduct
acceptancelimits.

49. QUALITY CONTROL TESTS
In-Process Tests parameters
1.Moisture contents of granules,
2.Drug content determination,
3.Assay of active ingredients,
4.Weight variation,
5.Thickness,
6.Hardness test, and
7.Disintegration time
Finished Product Tests
1.Diameter size and shape,
2.Thickness
3.Hardness
4.Friability
5.Weight variation test
6.Content uniformity test
7.Disintegration time
8.Dissolution test.

50. QUALITY CONTROL TESTS
In-ProcessTestsparameters
✓In-ProcessQualityControlsinvolvemonitoringandadapting
manufacturingprocessestomeetspecifications.
✓Controlsmanufacturingequipmentandenvironment.
✓Testsin-processmaterialsforidentity,strength,quality,andpurity.
✓Rejectedmaterialsareisolatedandquarantinedtopreventreusein
manufacturing.

51. QUALITY CONTROL TESTS
Finished Product Tests:
1)Appearance and Dimensions:
➢Tabletsofvarioussizesandshapesarepreparedbutgenerally,theyarecircularwith
eitherflatorbiconvexfaces.
➢VisualInspection:forUniformityincolour,shape,andsize.
➢Absenceofvisibledefects(e.g.,cracks,chips).
➢SizeandShape:
✓MeasuredusingVerniercalipersormicrometers.
✓Ensuresconsistencyintabletdimensions.
✓Tabletthicknessshouldbecontrolledwithina±5%variationofstandardvalue.
2)ThicknessTest
➢Thetabletthicknesscanvarywithoutanychangeinitsweight.
➢Thisisgenerallyduetothedifferenceindensityofgranules,pressureappliedfor
compression,andthecompressionspeed.
➢Thetabletthicknesscanbedeterminedwiththehelpofmicrometercallipers.
➢Thethicknessvariationlimitsallowedare±5%ofthetabletsize.Thevariationin
thicknessleadstocountingandpackingproblems.
➢Ensuresconsistentthicknessacrosstablets,whichaffectspackaginganddissolution.

52. QUALITY CONTROL TESTS
3)WeightVariationTest
➢Alltabletsshouldbeuniforminweight.Andvariationshouldfallwithinprescribedlimits.
➢Factorsaffectingtabletweightincludecompressionmachinetooling,headpressure,machinespeed,
andpowderflow.
➢Densityandparticlesizedistributionarecommonsourcesofweightvariation.
➢Minimizedoseandweightvariation.
Procedure
i.20tabletsweighedindividually.
ii.Averageweightcalculated.
iii.Notmorethan2tabletweightsmayexceedPharmacopoeia'spercentagedeviation.
iv.Noweightsshouldexceedtwicethepercentage.
v.IP/BPandUSPlimitsforweightvariationprovided.

53. QUALITY CONTROL TESTS
4)HardnessTest:
➢Tablethardness,alsoknownascrushingstrength,isakeyindicatoroftablet
qualityandrobustness.
➢Tablethardnessdependsonmaterialweight,compressionspace,pressure,and
excipienttypeandquantityused,aswellasthepressureappliedduring
compression.
➢Hardnesstestingmeasurestheforcerequiredtobreakorfractureatablet,
ensuringappropriatemechanicalpropertiesforhandling,packaging,andpatient
administration.

54. QUALITY CONTROL TESTS
4)HardnessTest:
1)MonsantoHardnessTester
➢Small, portable hardness tester introduced by Monsanto Chemical Company.
➢Composed of a spring compressed by a screw knob.
➢Tests tablets between fixed and moving jaws.
➢Adjusts indicator reading to zero.
➢Gradually increases force until tablet breaks.
➢Notes reading from scale indicating pressure required.
➢Hardness of 4kg suitable for tablets, 6kg or more for compact tablets.

55. QUALITY CONTROL TESTS
4)HardnessTest:
2)PfizerTabletHardnessTester
➢Tests tablet hardness using plier principle.
➢Fits with a dial for vertical holding of tablet.
➢Tablet is pressed until breaks.
➢Readings noted from pressure dial needle, expressed in kg or lbof force.

56. QUALITY CONTROL TESTS
5)FriabilityTest:
➢Friability test is performed to evaluate the ability of table tsto withstand abrasion in packing,
handling, and transporting.
➢The instrument used for this test is known as Friability test apparatus or friabilator.
➢Friability of a tablet can be determined in laboratory by RocheFriabilator.
➢This consists of a plastic chamber that revolves at 25rpm,
➢dropping the tablets through a distance of 6 inches in the friabilator,
➢which is then operated for 100 revolutions.
➢Tablets that lose less than 0.1-0.5% of their weight are considered acceptable.

57. QUALITY CONTROL TESTS
6)ContentUniformityTest:
➢Test ensures every tablet contains a stated amount of medicaments within prescribed limits.
➢Random selection of 30 tablets from a batch.
➢Assay procedures follow official book monographs.
➢Test passes if 9 tablets contain 85-115% of labeled drug content.
➢If conditions aren't met, 20 tablets are individually assayed, none falling outside the 85-115%
range.

58. QUALITY CONTROL TESTS
7)DisintegrationTest:
➢Determinesthetimerequiredforatablettobreakdownintosmallerparticles.
➢Thistestisveryimportantandnecessaryforallthecoatedoruncoatedtabletstobeswallowedbecause
thedissolutionratedependsuponthedisintegrationtimewhichultimatelyaffectstheabsorptionrateof
drugs.
TabletDisintegrationTestApparatus
➢Consistsofsixglasstubes,each3incheslong.
➢Tubesareopenatthetopandheldagainsta10-meshscreenatthebottom.
➢Tabletplacedineachtube.Basketrackwithtubesisplacedinabeakercontaining1literofwater,
simulatedgastricfluid,orsimulatedintestinalfluid.
➢Temperaturemaintainedat37±2°C.
➢Onupwardmovement,thetabletremains2.5cmbelowtheliquidsurface.
➢Ondownwardmovement,thetabletremains2.5cmabovethebottomofthebeaker.
➢Basketmovesupanddownthroughadistanceof5-6cmatafrequencyof28-32cyclesper
minute.
➢Perforatedplasticdiscscanbeplacedoneachtablettopreventfloating.
Disintegration Criteria:
Tablets should disintegrate, and all particles should pass through the 10-mesh screen within the specified
time. Any residue left must form a soft mass

59. QUALITY CONTROL TESTS
7)DisintegrationTest:
Disintegration Time
For Uncoated Tablets: 5-30 min.
For Coated Tablets: 1-2 hours.

60. QUALITY CONTROL TESTS
8)DissolutionrateTest:
➢Dissolutionistheprocessinwhichsolutedissolvesintosolventorsolution.
➢Measurestherateatwhichatabletdissolvesinaspecifiedmedium,determiningdrug
releaseandavailabilityforabsorption.
➢Thedissolutionrateofasoliddrugaffectsitsabsorptionandphysiologicalavailability
inthebloodstream.
➢Determiningthedissolutionrateisessentialforensuringproperdrugabsorptionand
therapeuticefficacy
➢U.S.P.specifiesthedissolutiontestmediumandvolume,apparatustype,shaftrpm,
timelimit,andassayprocedure.

61. QUALITY CONTROL TESTS
8)DissolutionrateTest:
➢Twotypesofapparatusesareused:Apparatus-1(BasketType)and
Apparatus-2(PaddleType).
Apparatus-1(BasketType)
➢Includesastainlesssteelbasket,a1000mlglassvessel,avariable
speedmotor-drivenstirrer,andathermostaticallycontrolledwater
bath.
Procedure:
➢Tabletplacedinwiremeshbasketconnectedtovariablespeedmotor.
➢Basketimmersedindissolutionmediumin1000mlcylindricalflask.
➢Flaskmaintainedat37±0.5°Ctemperatureviaconstanttemperature
bath.
➢Motoradjustedtoturnshaftataspecifiedspeed.
➢Samplewithdrawnatspecifiedintervalstodeterminedrug
amount.

62. QUALITY CONTROL TESTS
8)DissolutionrateTest:
Apparatus-2(PaddleType).
➢Components:Paddle,1000mlvessel,motorandshaft,andthermostablewaterbath.
➢Tabletplacedinthevessel,paddlerotatestosimulateinvivoconditions.
Procedure:
➢Fillvesselwithspecifieddissolutionmedium,placetabletatbottom.
➢Startmotor,setpaddlerotationspeed.
➢Flaskmaintainedat37±0.5°Ctemperatureviaconstanttemperaturebath.
➢Samplewithdrawnatspecifiedintervalstodeterminedrugamount.
➢Commonlyusedforimmediate-release,sustained-release,anddelayed-releasetablet
formulations.

63. QUALITY CONTROL TESTS