1. 11
Tablets - lTablets - l
By fagosonBy fagoson
Department of PharmacyDepartment of Pharmacy
NUBNUB
Pharmaceutical Technology

2. 22
““A tablet is a solid single unit dosage formA tablet is a solid single unit dosage form
containing one or more active ingredients withcontaining one or more active ingredients with
or without auxillary substances, prepared byor without auxillary substances, prepared by
compression and molding.”compression and molding.”
IntendedIntended mainlymainly for oral administrationfor oral administration
Most commonly are disk shaped with convex surfacesMost commonly are disk shaped with convex surfaces
Available in special shape like round, oval, oblong,Available in special shape like round, oval, oblong,
cylindrical, square, triangularcylindrical, square, triangular
Widely used solid dosage form because they offer aWidely used solid dosage form because they offer a
number of advantages to the patient, prescriber,number of advantages to the patient, prescriber,
manufacturer and manufacturing pharmacistmanufacturer and manufacturing pharmacist

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Essential qualities of a good TabletsEssential qualities of a good Tablets
--They should be accurate and uniform inThey should be accurate and uniform in
weightweight
--The drugs should be uniformly distributedThe drugs should be uniformly distributed
throughout the tabletsthroughout the tablets
-The size and shape should be reasonable for-The size and shape should be reasonable for
easy administrationeasy administration
--The tablets should not be too hard that it mayThe tablets should not be too hard that it may
not disintegrate in the Stomachnot disintegrate in the Stomach
-There should not be any incompatibilities-There should not be any incompatibilities
--They should be chemically and physicallyThey should be chemically and physically
stable during storage . Cont.stable during storage . Cont.

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Essential qualities of a good TabletsEssential qualities of a good Tablets
- They should not break during transportation- They should not break during transportation
or crumble in the hands of the patientor crumble in the hands of the patient
- They should be attractive in appearances- They should be attractive in appearances
- There should not be any manufacturing- There should not be any manufacturing
defects like cracking, chipping discolourationdefects like cracking, chipping discolouration
-- After disintegration it should release theAfter disintegration it should release the
drug readilydrug readily
- They should be easy and economical in- They should be easy and economical in
productionproduction..

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AdvantagesAdvantages
- Offer greatest dose precision and the least- Offer greatest dose precision and the least
content variabilitycontent variability
-- easy to be swallowed or administeredeasy to be swallowed or administered
- easy to handle and carry by the patient- easy to handle and carry by the patient
- economical, manufacturing cost are low,- economical, manufacturing cost are low,
manufacturing speed is quite highmanufacturing speed is quite high
- most stable with respect to physical, chemical- most stable with respect to physical, chemical
and microbiological attributesand microbiological attributes
-- Bitter, unpleasant taste and nauseous odour ofBitter, unpleasant taste and nauseous odour of
medicaments can be easily masked bymedicaments can be easily masked by
administering in the form of coated tabletadministering in the form of coated tablet

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Advantage (Continued)Advantage (Continued)
- product identification is probably the easiest- product identification is probably the easiest
because of the variety of shapes and colours ofbecause of the variety of shapes and colours of
tablets that are possibletablets that are possible
- the lightest and the more compact of all dosage- the lightest and the more compact of all dosage
formsforms
- the easiest and the cheapest to pack and transport- the easiest and the cheapest to pack and transport
- don’t require any measurement of dose- don’t require any measurement of dose

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Advantage (continued)Advantage (continued)
Can be divided into halves, quarters by drawingCan be divided into halves, quarters by drawing
lines during manufacture to facilitate breakagelines during manufacture to facilitate breakage
whenever a fractional dose is requiredwhenever a fractional dose is required
Lend themselves to certain special release profileLend themselves to certain special release profile
such as enteric or delayed release productssuch as enteric or delayed release products
Attractive and elegant in appearanceAttractive and elegant in appearance

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In Summary Solid Dosage Forms, Most
Notably Tablets Provide Advantages
To the pharmacist
in storage, dispensing, and control
convenience of use
To the patient
To the physician
cheaper due to mass production
and easier to manufacture,
simplicity, economy, stability,
and convenience
To the
manufacturer
of product identification, dosage
accuracy and precision, improved
control and more reliable therapy

9. 99
DisadvantagesDisadvantages
AmorphousAmorphous and Low density drugs are difficult toand Low density drugs are difficult to
compress.compress.
High dosesHigh doses are difficult to formulate as tablet dosageare difficult to formulate as tablet dosage
form.form.
BitterBitter tastingtasting and objectionableand objectionable odouodour drugs requirer drugs require
special treatment like coating or encapsulation andspecial treatment like coating or encapsulation and
increase the cost.increase the cost.
Drugs that are sensitive toDrugs that are sensitive to oxygenoxygen or atmosphericor atmospheric
moisture may also require special coating as well as costlymoisture may also require special coating as well as costly
packaging which may increase the overall cost of finishedpackaging which may increase the overall cost of finished
productproduct

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Disadvantage (Continued)Disadvantage (Continued)
Drugs with poorDrugs with poor wettingwetting and slow dissolution propertiesand slow dissolution properties
are difficult to convert into tablets which will provide fullare difficult to convert into tablets which will provide full
drug bioavailability.drug bioavailability.
Drugs that areDrugs that are liquidliquid at room temperature can not beat room temperature can not be
formulated in tablet dosage formformulated in tablet dosage form
A major disadvantage with respect to convenience ofA major disadvantage with respect to convenience of
patients is the difficulty ofpatients is the difficulty of swallowingswallowing specially byspecially by childrenchildren
and ill patientsand ill patients

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DifferentDifferent TypesTypes of Tabletsof Tablets
Classified into a number of categories, based onClassified into a number of categories, based on
theirtheir
-Their methods of manufacture-Their methods of manufacture
-Type of drug delivery system-Type of drug delivery system
- Formulation and Functions- Formulation and Functions
**Not all classes are entirely different but mostly**Not all classes are entirely different but mostly
overlap each other, such as,overlap each other, such as,
- Chewable and Effervescent tablets are single- Chewable and Effervescent tablets are single
layered uncoated tabletslayered uncoated tablets

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Classification (continued)Classification (continued)
Table1. Classified based on the method of manufacture andTable1. Classified based on the method of manufacture and
type of drug deliver systemtype of drug deliver system
(A) Tablets ingested orally:(A) Tablets ingested orally:
-- Compressed tablet, e.g. Paracetamol tablet
– Multiple compressed tablet
– Delayed release tablet, e.g. Enteric coated Bisacodyl tablet
– Sugar coated tablet, e.g. Multivitamin tablet
– Film coated tablet, e.g. Metronidazole tablet
– Chewable tablet, e.g. Antacid

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Classification (continued)Classification (continued)
(B) Tablets used in oral cavity :(B) Tablets used in oral cavity :
– Buccal tablet, e.g. Vitamin-c tablet
– Sublingual tablet, e.g. Vicks Menthol tablet
– Troches or lozenges
– Dental cone
(C) Tablets administered by other routes:(C) Tablets administered by other routes:
- Implantation tablet
- Suppositories or Inserts, e.g. Clotrimazole tablet

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(D) Tablets used to prepare solution:(D) Tablets used to prepare solution:
– Effervescent tablet, e.g. Dispirin tablet (Aspirin)
– Dispensing tablet, e.g. Enzyme tablet (Digiplex)
– Hypodermic tablet
– Tablet triturates e.g. Enzyme tablet (Digiplex)

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Standard compressed tabletStandard compressed tablet
-- Prepared by single compressionPrepared by single compression
- employ any of the three basic methods of manufactures:- employ any of the three basic methods of manufactures: wetwet
granulation, dry granulation and direct compression.granulation, dry granulation and direct compression.
- most of the tablets containing drugs intended to exert a local- most of the tablets containing drugs intended to exert a local
effect in the GIT are of this type (antacids and adsorbents)effect in the GIT are of this type (antacids and adsorbents)
-- Other drugs in this group are intended to produce systemicOther drugs in this group are intended to produce systemic
effect.effect.
-- Tablets break up and particle deaggregation are importantTablets break up and particle deaggregation are important

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Multiple compressed TabletMultiple compressed Tablet
Tablets of this category are usually prepared for one ofTablets of this category are usually prepared for one of
the two reasons:-the two reasons:-
a. to separate physically or chemically incompatiblea. to separate physically or chemically incompatible
ingredientsingredients
b. to produce repeat action or prolonged action productsb. to produce repeat action or prolonged action products
-- layered tablets consist of parallel layers obtained bylayered tablets consist of parallel layers obtained by
successive compression of particles of different comp.successive compression of particles of different comp.
- press coated or dry coated tablets are prepared- press coated or dry coated tablets are prepared
by compressing a layer of granules over a previouslyby compressing a layer of granules over a previously
compressed tablets. (manesty drycota).compressed tablets. (manesty drycota).

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The layered tablets are rapid, surface contact betweenThe layered tablets are rapid, surface contact between
layers is lessened, production is simpler so preferred.layers is lessened, production is simpler so preferred.
The shortcomings of this category of dosage form forThe shortcomings of this category of dosage form for
repeat – action products is that its performance isrepeat – action products is that its performance is
highly dependant on gastric empting.highly dependant on gastric empting.
XX,XX, If the second layer or core tablet quickly leaves theIf the second layer or core tablet quickly leaves the
stomach following release of the initial fast releasestomach following release of the initial fast release
dose, an entirely different blood level profile resultsdose, an entirely different blood level profile results
than if there is a several hour or longer delay beforethan if there is a several hour or longer delay before
the second fraction is emptied.the second fraction is emptied.
- this is the reason that relatively few repeat –action or- this is the reason that relatively few repeat –action or
controlled release products using this approach arecontrolled release products using this approach are
marketed.marketed.

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Repeat action tabletsRepeat action tablets
In addition to compressed tablets, sugar coated tabletIn addition to compressed tablets, sugar coated tablet
may also employed.may also employed.
The core tablet is usually coated with shellac or anThe core tablet is usually coated with shellac or an
enteric polymer so that it will not release the loadingenteric polymer so that it will not release the loading
drug in the stomach.drug in the stomach.
The second dose of drug is then added in the sugarThe second dose of drug is then added in the sugar
coating.coating.

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Delayed action and enteric coated tabletDelayed action and enteric coated tablet
The delay action tablet dosage form is intended toThe delay action tablet dosage form is intended to
release a drug after some time delay or after therelease a drug after some time delay or after the
tablet has passed through the part of GI tract intotablet has passed through the part of GI tract into
another.another.
The enteric coated tablet is the most commonThe enteric coated tablet is the most common
exampleexample
All enteric coated tablets are a type of delayedAll enteric coated tablets are a type of delayed
action tablet but not all delayed action tablet areaction tablet but not all delayed action tablet are
entericenteric
Cellulose acetate phthalate, Polyvinyl acetateCellulose acetate phthalate, Polyvinyl acetate
phthalate, Hydroxypropyl methyl cellulose phthatephthalate, Hydroxypropyl methyl cellulose phthate
have come into use for thishave come into use for this ..
These polymers being acid esters, are insoluble inThese polymers being acid esters, are insoluble in
gastric media that have a pH up to about 4.gastric media that have a pH up to about 4.

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Chewable tabletsChewable tablets
Are compressed tablets which have a smooth, rapid
disintegration when chewed or allowed to dissolve in
the mouth and contains a creamy base of a specially
flavored and colored mannitol.
Two major advantages are,Two major advantages are,
a.The dose of most antacid is large so that the typicala.The dose of most antacid is large so that the typical
antacid tablet would be too large to swallowantacid tablet would be too large to swallow
b.The activity of antacid is related to its particle size. Ifb.The activity of antacid is related to its particle size. If
the tablet is chewed prior to swallowing better acidthe tablet is chewed prior to swallowing better acid
neutralizing may be possible from a given antacidneutralizing may be possible from a given antacid
dosedose

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Xylitol may be used in the preparation of sugar-
free chewable tablets. Xylitol is sweeter than
mannitol.
lubricant and binders must not affect the texture
or desired hardness of the tablet
colorant and tart or fruity flavorants are
commonly employed to enhance the appeal of
the tablets
Examples of chewable tablets: Calcium
carbonate - antacids; Erythromycin - antibiotics;
Didanosine - anti-infectives; Carbamazepine -
anticonvulsants; Isosorbide dinitrate -
vasodilator; Acetaminophen - analgesics;
various vitamins and cold-allergy combination
tablet

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Tablets used in the oral cavityTablets used in the oral cavity
This type of tablet are placed in the mouth but notThis type of tablet are placed in the mouth but not
swallowed.swallowed.
*Buccal and sublingual tablets*Buccal and sublingual tablets
These tablets , though not swallowed, are intended toThese tablets , though not swallowed, are intended to
provide systemic drug action.provide systemic drug action.
These are small, flat, usually oval dosage forms to beThese are small, flat, usually oval dosage forms to be
inserted in the buccal , or cheek, pouch (buccal tablet) orinserted in the buccal , or cheek, pouch (buccal tablet) or
beneath the tongue (sublingual tablets).beneath the tongue (sublingual tablets).
The drug is absorbed directly through the oral mucosa,The drug is absorbed directly through the oral mucosa,
thereby avoiding the acid and enzymatic environment ofthereby avoiding the acid and enzymatic environment of
the stomach and the drug metabolizing enzymes of thethe stomach and the drug metabolizing enzymes of the
liver.liver.

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Drugs are commonly administered by the oralDrugs are commonly administered by the oral
mucosal routemucosal route::
the vasodilator glyceryl trinitratethe vasodilator glyceryl trinitrate:: Steroids, such asSteroids, such as
methyl testosteronemethyl testosterone,, testosterone propionatetestosterone propionate,,
estradioestradiol: and, possibly, some miscellaneousl: and, possibly, some miscellaneous
hormones and drugshormones and drugs, such as, such as pancreaticpancreatic
lipotropic hormone factors,lipotropic hormone factors, hesperidinhesperidin, and, and
nicotinic acid.nicotinic acid.
Drugs that may be absorbed via the oralDrugs that may be absorbed via the oral
mucosa have several possible advantagesmucosa have several possible advantages::
(1) Avoidance of the gastric environment and the(1) Avoidance of the gastric environment and the
decomposition it may produce with some steroids anddecomposition it may produce with some steroids and
hormone (2) a more rapid onset of drug action thanhormone (2) a more rapid onset of drug action than
occurs with tablets which are swallowed (3) Reduction ofoccurs with tablets which are swallowed (3) Reduction of
nausea, with drugs that produce this effect whennausea, with drugs that produce this effect when
swallowed (4) More efficient drug utilization (lower dose),swallowed (4) More efficient drug utilization (lower dose),
owing to avoidance of inactivation by liver drugowing to avoidance of inactivation by liver drug
metabolising enzymes.metabolising enzymes.

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. Drugs absorbed from the gastrointestinal tract enter the mesenteric. Drugs absorbed from the gastrointestinal tract enter the mesenteric
circulation which feeds directly into the liver via the portal vein. Drugcirculation which feeds directly into the liver via the portal vein. Drug
absorption from the oral cavity involves drug diffusion into the blood and lymphabsorption from the oral cavity involves drug diffusion into the blood and lymph
canals through the sublingual or oral mucosa. Blood is supplied to this regioncanals through the sublingual or oral mucosa. Blood is supplied to this region
via the external carotid artery and is returned via the jugular veins into thevia the external carotid artery and is returned via the jugular veins into the
general circulation rather than going directly to the portal vein. Many steroidsgeneral circulation rather than going directly to the portal vein. Many steroids
are either relatively or totally inert if ingested owing to inactivation by liverare either relatively or totally inert if ingested owing to inactivation by liver
enzymes. This loss of potency can be circumvented by other modes ofenzymes. This loss of potency can be circumvented by other modes of
administration such as intramuscular injection, implantation of tablets, use ofadministration such as intramuscular injection, implantation of tablets, use of
vaginal suppositories, or absorption through the oral mucosa. The lattervaginal suppositories, or absorption through the oral mucosa. The latter
method, in many instances, is preferable.method, in many instances, is preferable.
Since most drugs, including weakly acidic drug moieties, are probablySince most drugs, including weakly acidic drug moieties, are probably
absorbed primarily in the upper small intestine. The tablet must disintegrate,absorbed primarily in the upper small intestine. The tablet must disintegrate,
the drug dissolve, and the stomach empty at least partially before drugthe drug dissolve, and the stomach empty at least partially before drug
absorption begin. Therefore , a time lag of 30 minutes or more (correspondingabsorption begin. Therefore , a time lag of 30 minutes or more (corresponding
to the time required for the drug to be dissolved and leave the stomach) isto the time required for the drug to be dissolved and leave the stomach) is
typical before a drug effect is exerted after swallowing a tablet. on the othertypical before a drug effect is exerted after swallowing a tablet. on the other
hand , total drug absorption typically occurs within 30 minutes after buccal orhand , total drug absorption typically occurs within 30 minutes after buccal or
sublingual tablets have been administered and onset of action is common withsublingual tablets have been administered and onset of action is common with
vasodilator drugs..vasodilator drugs..
Buccal and sublingual tablets are designed not to disintegrate but to dissolveBuccal and sublingual tablets are designed not to disintegrate but to dissolve
slowly over a 15 to 30 minute period. The tablet composition should notslowly over a 15 to 30 minute period. The tablet composition should not
promote salivation, which would result in swallowing dissolved drug, therebypromote salivation, which would result in swallowing dissolved drug, thereby
circumventing the purpose of the buccal or sublingual tablets.circumventing the purpose of the buccal or sublingual tablets.

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Dental conesDental cones
The cones may contain an antibiotic orThe cones may contain an antibiotic or
antiseptic typically in a filler of Sodiumantiseptic typically in a filler of Sodium
bicarbonate, sodium chloride, amino acid,bicarbonate, sodium chloride, amino acid,
or lactose.or lactose.
The cones are formulated and compressionThe cones are formulated and compression
so that a small volume of serum or fluid willso that a small volume of serum or fluid will
cause disintegration and dissolution in 20 tocause disintegration and dissolution in 20 to
30 minutes.30 minutes.

27. 2727
Tablets administered by other routesTablets administered by other routes
Implantation tabletsImplantation tablets
This is also known as pellets, are small sterile tablets,This is also known as pellets, are small sterile tablets,
cylindrical shaped and usually not over 8 mm. in length, forcylindrical shaped and usually not over 8 mm. in length, for
subcutaneous implantation in man or animals to providesubcutaneous implantation in man or animals to provide
very prolonged drug effects – for 3 to 6 months or longer.very prolonged drug effects – for 3 to 6 months or longer.
In man, use of this dosage form is limited to very potentIn man, use of this dosage form is limited to very potent
drugs which are not orally absorbed, notably steroids suchdrugs which are not orally absorbed, notably steroids such
as Desoxycorticosterone, testosterone, or estradiol.as Desoxycorticosterone, testosterone, or estradiol.
The major advantage of the dosage form is to provideThe major advantage of the dosage form is to provide
continuous therapy over many months without the needcontinuous therapy over many months without the need
for repeated parenteral dosing. Over a long periods of timefor repeated parenteral dosing. Over a long periods of time
this form of therapy can be most economical. Also, it maythis form of therapy can be most economical. Also, it may
provide the most even and uniform hormone therapy.provide the most even and uniform hormone therapy.

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Implantation tabletsImplantation tablets
The immediate and potential disadvantage ofThe immediate and potential disadvantage of
implantation therapy are:implantation therapy are:
- the surgical technique which may be required- the surgical technique which may be required
for implantationfor implantation
- the difficulty of maintaining a constant drug- the difficulty of maintaining a constant drug
release rate as the pellet changes geometry withrelease rate as the pellet changes geometry with
dissolutiondissolution
- the possibility of a histopathological (tissue- the possibility of a histopathological (tissue
toxicity) reaction against the implanted ‘foreigntoxicity) reaction against the implanted ‘foreign
body’body’
-the need to employ a surgical technique to-the need to employ a surgical technique to
terminate the therapy should such terminationterminate the therapy should such termination
become necessarybecome necessary

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Vaginal tabletsVaginal tablets
Also called inserts, are generally ovoid orAlso called inserts, are generally ovoid or
pear shaped made by compression andpear shaped made by compression and
intended to undergo dissolution and drugintended to undergo dissolution and drug
release in the vaginal cavity.release in the vaginal cavity.
The tablets are usually used in the treatmentThe tablets are usually used in the treatment
of trichomonas vaginitis andof trichomonas vaginitis and
contain organic iodine (iodochlor orcontain organic iodine (iodochlor or
iodohydroxyquinoline compounds) or otheriodohydroxyquinoline compounds) or other
antiseptics, astringents, or steroids in aantiseptics, astringents, or steroids in a
soluble base of lactose or sodiumsoluble base of lactose or sodium
biocarbonate.biocarbonate.

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Effervescent tabletsEffervescent tablets
These tablet produce effervescence whenThese tablet produce effervescence when
added to cold water. Effervescence whichadded to cold water. Effervescence which
is usually carbon dioxide is generated dueis usually carbon dioxide is generated due
to chemical reaction which take placeto chemical reaction which take place
between a Bicarbonate and an acid (citricbetween a Bicarbonate and an acid (citric
acid and Tataric acid)acid and Tataric acid)
The effervescence causes rapidThe effervescence causes rapid
disintegration of the tablet and alsodisintegration of the tablet and also
increases the palatabilityincreases the palatability ।।