This document discusses different types of tablets and the tablet manufacturing process. It begins by defining what a tablet is and listing some key advantages such as precise dosing, low cost, and stability. It then describes different types of tablets including compressed, coated, chewable, and those for different routes of administration. The document outlines common excipients used in tablets and their functions. It explains the importance of granulation and describes different granulation methods including dry, wet, and direct compression. The wet granulation process is outlined in detail including mixing, granulation, and drying steps.

1. NARESH GORANTLA M.Pharm.., (Ph.D)
Asso. Professor,
Balaji college of Pharmacy,
Ananthapuramu

2. INTRODUCTION
• Tablet is defined as a compressed solid dosage
form containing medicaments with or without
excipients.
• According to the Indian Pharmacopoeia
Pharmaceutical tablets are solid, flat or
biconvex dishes, unit dosage form, prepared by
compressing a drug or a mixture of drugs, with
or without diluents.

3. ADVANTAGES :
• They are unit dosage form and offer the greatest capabilities of
all oral dosage form for the greatest dose precision and the least
content variability.
• Cost is lowest of all oral dosage form.
• Lighter and compact.
• Easiest and cheapest to package and strip.
• Easy to swallowing with least tendency for hang-up.
• Sustained release product is possible by enteric coating.

4. • Objectionable odour and bitter taste can be masked by coating
technique.
• Suitable for large scale production.
• Greatest chemical and microbial stability over all oral
dosage form.
• Product identification is easy and rapid requiring no additional
steps when employing an embossed and/or monogrammed
punch face.

5. DISADVANTAGES:
• Difficult to swallow in case of children and
Unconscious patients.
• Some drugs resist compression into dense compacts, owing to
amorphous nature, low density character.
• Drugs with poor wetting, slow dissolution properties, optimum
absorption high in GIT may be difficult to formulate or
manufacture as a tablet that will still provide adequate or full
drug bioavailability.
• Bitter testing drugs, drugs with an objectionable odor or drugs
that are sensitive to oxygen may require encapsulation or
coating. In such cases, capsule may offer the best and lowest
cost.

6. DIFFERENT TYPES OF TABLETS
(A)Tablets ingested orally:
1. Compressed tablet, e.g. Paracetamol tablet
2. Multiple compressed tablet
3. Repeat action tablet
4.Delayed release tablet, e.g. Enteric coated tablet
5. Sugar coated tablet, e.g. Multivitamin tablet
6. Film coated tablet, e.g. Metronidazole tablet
7. Chewable tablet, e.g. Antacid tablet
(B)Tablets used in oral cavity:
1. Buccal tablet, e.g. Vitamin-c tablet
2. Sublingual tablet, e.g. Vicks Menthol tablet
3. Troches or lozenges
4. Dental cone

7. (c) Tablets administered by other route:
1. Implantation tablet
2. Vaginal tablet, e.g. Clotrimazole tablet
(D) Tablets used to prepare solution:
1. Effervescent tablet, e.g. Disprin tablet (Aspirin)
2. Dispensing tablet, e.g. Enzyme tablet (Digiplex)
3. Hypodermic tablet
4. Tablet triturates e.g. Enzyme tablet (Digiplex)

8. FORMULATION OF TABLETS
In addition to active ingredients, tablet contains a number of inert
materials known as additives or excipients. Different excipients
are:
1. Diluent
2. Binder and adhesive
3. Disintegrents
4. Lubricants and glidants
5. Colouring agents
6. Flavoring agents
7. Sweetening agents

9. EXCIEPIENTS- FUNCTIONS
• Impart weight, accuracy, & volume(its allow accuracy of dose)
• Improve solubility
• Increase stability
• Enhance bioavailability
• Modifying drug release
• Assist product identification
• Increase patient acceptability
• Facilitate dosage form design

10. • 1. Diluent: Diluents are fillers used to make required bulk of the
tablet when the drug dosage itself is inadequate to produce the
bulk. Secondary reason is to provide better tablet properties such
as improve cohesion, to permit use of direct compression
havemanufacturing or to promote flow. A diluent should
following properties:
1. They must be non toxic
2.They must be commercially available in acceptable
grade
3. There cost must be low
4. They must be physiologically inert
5.They must be physically & chemically stable by
themselves & in combination with the drugs.
6. They must be free from all microbial contamination.
7. They do not alter the bioavailability of drug.
8. They must be color compatible.

11. COMMONLY USED TABLET DILUENTS
1. Lactose-anhydrous and spray dried lactose
2. Directly compressed starch-Sta Rx 1500
3. Hydrolyzed starch-Emdex and Celutab
4. Microcrystalline cellulose-Avicel (PH 101and PH 102)
5. Dibasic calcium phosphate dehydrate
6. Calcium sulphate dihydrate
7. Mannitol
8. Sorbitol
9. Sucrose- Sugartab, DiPac, Nutab
10. Dextrose

12. 2. Binders and Adhesives: These materials are added
either dry or in wet- form to form granules or to form
cohesive compacts for directly compressed tablet.
• Example: Acacia, tragacanth- Solution for 10-25% Conc.
• Cellulose derivatives- Methyl cellulose, Hydroxy
propyl methyl cellulose, Hydroxy propyl cellulose
• Gelatin- 10-20% solution
• Glucose- 50% solution
• Polyvinylpyrrolidone (PVP)- 2% conc.
• Starch paste-10-20% solution
• Sodium alginate
• Sorbitol

13. 3. Disintegrants: Added to a tablet formulation to facilitate
its breaking or disintegration when it contact in water in
the GIT.
• Example: Starch- 5-20% of tablet weight.
• Starch derivative – Primogel and Explotab (1-8%)
• Clays- Veegum HV, bentonite 10% level in colored tablet only
• Cellulose
• Cellulose derivatives- Ac- Di-Sol (sodium carboxy methyl
cellulose)
• Alginate
• PVP (Polyvinylpyrrolidone), cross-linked

14. • Superdisintegrants: Swells up to ten fold within 30
seconds when contact water.
• Example: Crosscarmellose- cross-linked
Crosspovidone- cross-linked povidone (polymer),
cellulose,
Sodium
starch glycolate- cross-linked starch. These cross-linked
products swells with in 30 seconds when in contact with
water.
• A portion of disintegrant is added before granulation and a
portion before compression, which serve as glidants or
lubricant.

15. • 4. Lubricant and Glidants: Lubricants are intended to
prevent adhesion of the tablet materials to the surface of
dies and punches, reduce inter particle friction and may
improve the rate of flow of the tablet granulation.
Glidants are intended to promote flow of granules or powder
material by reducing the friction between the particles.
• Example: Lubricants- Stearic acid, Stearic acid salt - Stearic
acid, Magnesium stearate, Talc, PEG (Polyethylene glycols),
Surfactants
• Glidants- Corn Starch – 5-10% conc., Talc-5% conc., Silica
derivative - Colloidal silicas such as Cab-O-Sil, Syloid, Aerosil
in 0.25-3% conc.

16. • 5. Coloring agent: The use of colors and dyes in a tablet has
three purposes:
(1) Masking of off color drugs
(2) Product Identification
(3) Production of more elegant product
• All coloring agents must be approved and certified by FDA.
Two forms of colors are used in tablet preparation – FD &C
and D & C dyes. These dyes are applied as solution in the
granulating agent or Lake form of these dyes. Lakes are dyes
absorbed on hydrous oxide and employed as dry powder
coloring.
• Example: FD & C yellow 6-sunset yellow,FD & C yellow 5-
Tartrazine ,FD & C green 3- Fast Green,FD & C blue 1-
Brilliant Blue ,FD & C blue 2 - Indigo carmine

17. 6. Flavoring agents: For chewable tablet- flavor oil are used
7. Sweetening agents: For chewable tablets: Sugar,
mannitol.
• Saccharine (artificial): 500 time’s sweeter than sucrose
• Disadvantage: Bitter aftertaste and carcinogenic
• Aspartame (artificial)
• Disadvantage: Lack of stability in presence of moisture.

18.  The following stepsare involved in the manufacturing of
Tablets:
 Weighing of the ingredients.
 Mixing the powdered ingredients andexcipients.
 Converting the mixed ingredients intogranules.
 Compression of granules to prepare tablets.
MANUFACTURING OF TABLETS

19.  Granules are aggregations of fine particles of powders in
a mass of about spherical shape.

20. • To prevent segregation of the constituents of the powder mix.
• To improve the flow properties of the mix.
• To improve the compression characteristics of the mix.
• To reduce caking of hygroscopic materials on storage.
• As granules are denser than the parent powder mix, occupy
less volume per unit weight. Easy for storage.
Why we prepare granules when we have powders.?

21. GRANULATION TO PREVENT SEGREGATION

22. Some of the available methods in the industrial field
for the preparation of granules:
1. Dry Granulation
2. Wet granulation
3. Direct compression
METHODS OF GRANULATION

23. GRANULATION METHODS

24. DRY GRANULATION
• Dry granulation methods, powder particles are
aggregated under high pressure.
• The dry granulation process is use to form granules
without using liquid solution because the product to be
granulated may be sensitive to moisture and heat.
• Two method are used for dry granulation.
1. Slugging
2. Roller compaction

25. 1. SLUGGING
• The powders is forced into the dies of a large
capacity tablet press and is compacted by means
flat and faced punches , the compacted mass is
called Slugs and the process is called to as a
Slugging.
• The resulting slugs are milled to yield granules.

26. 2. ROLLER COMPACTION
• This method is used for dry granulation on large
scale on a specially designed machine called
roller compactor.
• In this method powders is compressed in a roller
compactor forming a sheet or large pieces that are
broken down into a tablet granulation.

27. ROLLER COMPACTORS

28. WET GRANULATION
• Wet granulation involves the massing of a mix of
dry primary powder particles using a granulating
fluid.
• The fluid contain a solvent which must be
volatile so that it can be removed by drying.
• Typically liquid include water, ethanol or
isopropanol either alone or in combination.
• primary advantages of water are that:
• it is non-flammable, which means that
expensive safety precautions not be taken.

30. METHOD OF WET GRANULATION
• Mixing :-The first stage in the wet granulation
process is often a dry mixing stage in which the
active component is mixed with a diluents. The
purpose of the mixing stage is to ensure that the
powder blend and hence the resulting tablets are
homogeneous in content.
• Granulation :- Granulation is a unit operation in
which mixed powders are simultaneously mixed
with a suitable fluid, e.g. water, isopropanol or
ethanol.

31. • DRYING :- After the process of granulation, the
product exists as a wet mass from which the liquid
must be removed. Water is usually removed by
evaporation for which energy is needed.
• SEIVING :- When the drying process is
complete, it is likely that the product will have
cohered into relatively large masses, especially if
tray drying has been used. The dried material is
therefore passed through a sieve (usually 250–
700 mm) to break up aggregates and to give a
relatively uniformly sized granules.

32. • MIXING OF ADDITIVES :- A second mixing
stage now follows in which several important
ingredients of the formulation are added.
Glidant :- To increase flow of material during
manufacturing processes
Lubricant :- To avoid sticking with wall of dyes.
Disintegrating agent:- To disintegrate in GIT tract.

33. STAGES IN TABLET FORMATION
"COMPACTION CYCLE“
1- DIE FILLING.
2- TABLET FORMATION.
3- TABLET EJECTION.

34. 1- DIE FILLING:
Flow of powders (or granules) of the drug and excipients
from a hopper into the die. The die is closed at its lower end
by the lower punch.
2- TABLET FORMATION:
The upper punch descends powder and enters the die and
the powder is compressed until a tablet is formed. Lower
punch may be stationary or moving upward in the die. After
maximum applied force is reached, the upper punch leaves
the die by moving upward.
3- TABLET EJECTION:
The lower punch rises up until its tip reaches the die top.
The tablet is subsequently removed by a pushing device.

35. COMPRESSION MACHINES
 Thevarious typeof machines used for this purpose,
are:
1. Singlepunch tablet machinewhich may be hand
operated or electricallyoperated
2. Multi-punch tablet machine
3. Rotary tablet machine
4. Dry cota tabletmachine

36. SINGLE PUNCH TABLET
MACHINE
 Hopper shoe
 Lowerpunch
 Upperpunch
 Capacity regulator : Toadjust the
position of lower punch to
accommodate the requiredqty. of
granules by thedie.
 Ejection regulator
 Die
 Driving wheel

37. MULTI-PUNCH TABLET MACHINE
 In a multi-punch tablet machine thereare 2 to 12 dieson a
big platform.
 The working of this machine similar to that of a single
punch machine but in this machineone strokeas many
tablets are compressed.

38. ROTARYTABLETMACHINE
 It is used in large scale production unit.
 In this machine 1200 tabletsare prepared in one minute.
 There are 70 sets of dies &punches.
 A rotary tablet machine has a circularrotating head, carrying
a number of punch & diesassembles.
 There is uniform filling of thedie.
 In thatcompression of granules takes placeas the upper &
the lowerpunches pass between a pairof rollers.

39. DRYCOTATABLETMACHINE
 The machine is used for manufacturing of
multi- compressed, multi-coloured & press coatedtablets.
 In this machine tworotary machineswork simultaneously.
 The core tablet is prepared in one machine which
is transferred to thesecond machine forcompress
coating.

40. WORKING OF COMPRESSION
MACHINES
Machines built to compress tablets consist of:
1- Hopper: for holding granulations for compressing.
2- Feed frame: for distributing the materials into the
dies.
3- Dies: for controlling the size and the shape of the
tablet.
4- Punches: for compressing the granulations within
the dies.
5- Cam tracks for guiding the movement of the
punches.

41. COMPRESSION CYCLE
• Granules from hopper empty in the feed frame (A) containing
several interconnected compartments.
• These compartments spread the granulation over a wide area
to provide time for the dies (B) to fill.
• The pull down cam (C) guides the lower punches to the
bottom, allowing the dies to overfill
• The punches then pass over a weight-control cam (E), which
reduces the fill in the dies to the desired amount
• A swipe off blade (D) at the end of the feed frame removes
the excess granulation and directs it around the turret and
back into the front of the feed frame
• The lower punches travel over the lower compression roll (F)
while simultaneously the upper punches ride beneath the
upper compression roll (G)

42. • The upper punches enter a fixed distance into the dies, while
the lower punches are raised to squeeze and compact the
granulation within the dies
• After the moment of compression, the upper punches are
withdrawn as they follow the upper punch raising cam (H)
• The lower punches ride up the cam (I) which brings the
tablets flush with or slightly above the surface of the dies
• The tablets strike a sweep off blade affixed to the front of the
feed frame (A) and slide down a chute into a receptacle
• At the same time, the lower punches re-enter the pull down
cam (C) and the cycle is repeated

44. • Official tests:
1.Size and shape and appearance of tablet.
2.Content of active ingredient.
3.Uniformity of weight/weight variation test
4.Disintegration.
5.Dissolution.
• Unofficial tests:
1.Hardness test.
2.Friability
EVALUATION OF TABLETS

45. 1.GENERALAPPEARANCE :
The general appearance of a tablet is essential for
consumer acceptance. it involves:
 Size & Shape : Tablet thickness should be
controlled within a ± 5% variation of standard
value.
 Unique identification marking: These markings
include company name or symbol, product code,
product name etc.
 Organoleptic properties: Color distribution must be
uniform in comparison with the color of the standard.

46. weigh randomly 20 tablets individually in a batch.
Determine the average weight of 20 tablets.
Compare individual tablet weight to average weight
2.WEIGHT VARIATION TEST:
• As per I.P. ,
 If the tablet weight is,
 < 80mg , % deviation allowed up to 10%
80-250mg , % deviation allowed up to 7.5%
> 250mg , % deviation allowed up to 5%
If any of the tablet deviates, another 10 tablets are selected
from the same batch and the procedure is repeated.
Of 30 tablets , not more than 1 tablet should deviate.

47. It is used to ensure that every tablet contains the amount
of drug substance intended with little variation.
Procedure:
o 10 tablets are assayed,
o 9 tablets should have % limit of 85-115%.
o If more than 1 tablet deviates from 85-115%,
o Another 20 tablets are assayed
o Not more than 1 tablet should have the % limit of 75-
125%
3.CONTENT UNIFORMITY TEST:

48. 4.Disintegration test:
Disintegration is the breakdown of tablet crust into
finely divided particulate matter or into granules
once the tablet is exposed to the gastric fluids .
Type of tablets Time Of
disintegration
uncoated
conventional tablets
15min
sugar coated tablets 60 min.
film coated tablets 30 min

49. • For Uncoated tablets:
1. Start the disintegration test on 6 tablets, if one or two tablets from the 6
tablets fail to disintegrate completely within 30min, repeat the same test
on another 12 tablet.
2. NLT 16 tablets should disintegrate completely within the time and
if more than two tablets (from the 18) fail to disintegrate, the batch
must be rejected.
• For Coated tablets:
1. Put the tablet in the apparatus in water or 0.1 N HCl for 30min at 37oC
(according to the U.S.P).
4. So 16 tablets from the 18 must completely disintegrate within the time.
5. If two or more tablets do not disintegrate within the time the batch is
rejected.
• For Enteric coated tablets:
1. Put in simulated gastric fluid for two hours (emptying time)
2. Put in phosphate buffer (PH 6.8) for one hour.
3. If one or two tablets fail to disintegrate repeat on 12 tablets.
4. So 16 tablets should disintegrate. If more than two tablets fail to
disintegrate, reject the batch.

50. 5. DISSOLUTION TEST (U.S.P.): IT is the solubilization of the
drug or active moiety in to the dissolution media.
Different types of dissolution apparatus:
Apparatus -I-Rotating Basket type.
Apparatus -II- Rotating Paddle type.
Apparatus-3-Reciprocating cylindrical type.
Apparatus-4-Flow through cell.
Apparatus-5-Paddle over disk.
Apparatus-6-Cylindrical apparatus.
Apparatus-7-Reciprocating disc apparatus.

51. • Method:
• Place 1000 ml of water into the vessel. Place the specified
number of tablets in the dry basket and set the apparatus. Start
the motor and adjust the temperature and rotation speed to 36.5◦c
to 37.5◦c and 100 rpm or as given in monograph. Withdraw the
sample after specified time intervals. Filter and determine the
amount of active ingredient present in it by the method given in
the monograph.
• Acceptance criteria:
1. S1= 6 tablets are taken Acceptable: If all of the tablets are not less
than Q ±5%
2. If S1 fails, S2=S1+6 tablets are taken Acceptable: If average of 12
tablets is ≥Q and no tablet is less than Q-15%
3. If S2 fails, S3= 12+12 tablets are taken Average of 24 ≥ Q% not more
than 2 tablets should be less than Q-15% and None should be less than
Q-25%

52. It is defined as the force required to break a tablet in a
diametric compression . Tablet requires a certain amount of
strength or hardness and resistance to friability to withstand
mechanical shocks of handling in manufacture, packaging and
shipping
Types of hardness testers used.
1. Monsanto hardness tester .
2. Strong cob tester.
3. Pfizer tester.
For, Conventional tablets hardness :2.5- 5 kg/cm2 Dispersible/
chewable tablets hardness: 2.25- 2.5 kg/cm2 Extended
release tablets hardness : 5- 7.5 kg/cm2
6. HARDNESS TEST:

53.  The instrument used is Roche friabilator.
 It consists of a drum having 280-290mm diameter with a
thickness of 30mm. A drum is mounted on a horizontal axis
of a drive motor.
 Drum is operated at a speed of 25rpm. & Allowed revolutions
for each tablet is 100.
 Allowable range: loss 0.5 - 1% weight
7. FRIABILITY TEST:

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